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I-1.i. 2040 Comprehensive Plan- i. Surface Water ` T Y I —* I G ,n w H Ae CITY OF CIIANIIASSEN SS Chanhassen is a Community for Life-Providing for Today and Planning for Tomorrow MEMORANDUM TO: Planning Commission FROM: Vanessa Strong, Water Resource Coordinator DATE: September 26, 2017 SUBJ: 2018-2027 Local Surface Water Management Plan Discussion Background The City of Chanhassen manages its lakes, streams, and wetlands through its Local Stormwater Management Plan(LWMP) and in partnership with four Watershed Management Organizations (WMO): the Carver County WMO, Riley-Purgatory-Bluff Creek, Minnehaha Creek, and the Lower Minnesota River Watershed Districts. The LWMP identifies areas of focus during the period 2018-2027,providing a guide to projects and programs to protect and improve these water resources. Parts of the city drain to either Lake Minnewashta or Christmas Lake and then to Lake Minnetonka. The rest of the city drains to the Minnesota River. There are 9 major lakes in Chanhassen, 2 natural system lakes and hundreds of smaller ponds and wetlands including the Seminary Fen. Bluff Creek is the longest stream in the city, flowing just over 7 miles southeast to Rice Lake in the Minnesota River floodplain. The headwaters of Riley Creek is Lake Ann. From the lake's outlet Riley Creek flows southeast through Lake Susan, Rice Marsh Lake, and Riley Lake, then outlets that lake and flows to the Minnesota River. Assumption Creek, located in the Minnesota River Valley, is a DNR-designated trout stream. Where known,the LWMP includes information about the water quality in these lakes and streams, and the steps the city and WMOs are taking to manage them. Included in the LWMP is an update to the city's storm drainage models. These models break the drainage system down into ten subwatersheds, and model the network of storm sewers, channels, ponds, and wetlands that store and convey rainwater and snowmelt. These models can be used to ensure pipes and ponds are of sufficient size and to predict where flooding might occur during large rainstorms. PH 952.227.1100• www.ci.chanhassen.mn.us• FX 952.227.1110 7700 MARKET BOULEVARD • PO BOX 147 • CHANHASSEN • MINNESOTA 55317 Planning Commission 2018-2027 Local Surface Water Management Plan Discussion October 3, 2017 Page 2 of 3 Discussion A number of water resources-related problems, issues, and requirements were identified in this planning process. These include: • The reissue of the State of Minnesota's NPDES General Stormwater Permit in 2013 requires local governments such as Chanhassen to adopt and enforce standards and ordinances for development and redevelopment which limits stormwater runoff from sites over one acre in size. • New or expanded maintenance and administrative responsibilities are required in the NPDES permit to control runoff and protect and improve water quality from city owned or maintained land. • All 4 WMO's are updating their 10 year Comprehensive Plans. The city is required to amend their LWMP to be consistent with each WMO • In order to maintain and/or obtain primary responsibility for managing local water resources additional ordinance revisions are required. The alternative is to defer the authority to the local WMO • Some of the lakes and streams in the city do not meet the state's water quality standards for recreation and aquatic life. • Stream gullies and escarpments are contributing excess sediment into Bluff Creek and the Minnesota River. To address these issues,the LWMP sets forth six goals as well as policies and action steps it proposes to take. The LWMP's Implementation Plan includes capital improvement projects, city- conducted as well as partnership projects with the WMOs and other partners;management programs such as education and outreach and water quality monitoring; operations and maintenance activities such as street sweeping, stormwater system inspections and repairs, road salt management and staff training; and ordinance revisions. While the LWMP is a ten-year plan, Goal 1. Promote abstraction through infiltration, reuse and other methods where practicable to do so to provide flood protection, ground water recharge and improved water quality. Goal 2. Achieve water quality standards in lakes, streams, and wetlands consistent with their designated uses and established classifications. Goal 3. Protect and rehabilitate wetlands to maintain or improve their function and value. Goal 4. Prevent contamination of the aquifers and promote groundwater recharge to maintain base flows in streams and wetlands. Goal 5. Maintain primary responsibility for managing water resources at the local level where efficient to do so but continue coordination and cooperation with other agencies and organizations. Goal 6. Provide information and educational resources to improve knowledge and promote an active public role in management of water resources. Planning Commission 2018-2027 Local Surface Water Management Plan Discussion October 3, 2017 Page 3 of 3 the Implementation Plan is reviewed annually, and new projects and programs may be added as more information is available and as opportunities arise. Recommendation Request the Planning Commission provide feedback and comment on the LWMP goals, and identify any additional issues we should address so we can finalize the draft document. Attachments • Permit Requirement Table of Agencies • Appendix A Land and Water Resources • Public Input Summary Report G:\PLAN\2040 comp Plan\Planning Commission Memo 9_27_17 I Development and Redevelopment Project Review/Permit Requirements of Various Agencies REVISED 9/12/2017 Carver County WMO Riley-Purgatory—Bluff Cr WD Lower Minnesota River WD Minnehaha Creek WD Standard Plan: December 14,2011 Chanhassen NPDES General Permit NPDES Construction Permit Plan:October 26,2010 Plan:January 26,2011 Plan:July 5,2007 Rules: 10/15/16 Rules: Effective 1/1/15 Rules:Cities;new standards Rules:6/6/14 pending 9/17 Threshold:single family Unknown Disturb>1 acre of land, or Disturb>1 acre of land, or Create 1>impervious or a. Land-disturbing activities Disturb>1 acre of land >_1 acre where more than 20% residential new development part of common development part of common development >10,000 sf in sensitive areas that will disturb 50 cubic yards Pending Draft:within the of site is or will be impervious >1 acre >1 acre or more of earth; HVRA Overlay, create>10,000 b. Land-disturbing activities sq ft new impervious area that will disturb 5,000 square feet or more of surface area or vegetation; or c.Subdivision of a parcel into three or more residential lots. Threshold: non-residential Unknown Disturb>1 acre of land,or Disturb>1 acre of land,or Create 1>impervious or a. Land-disturbing activities Disturb>1 acre of land >1 acre where more than 20% new development part of common development part of common development >10,000 sf in sensitive areas that will disturb 50 cubic yards Pending Draft:within the of site is or will be impervious >1 acre >1 acre or more of earth; HVRA Overlay,create>10,000 b. Land-disturbing activities sq ft new impervious area that will disturb 5,000 square feet or more of surface area or vegetation; or Threshold:single family Unknown Disturb>1 acre of land, or Disturb>1 acre of land, or Additions:Create>1 acre Same as above, except where Disturb>1 acre of land <_1 acre; requirements vary by residential redevelopment part of common development part of common development impervious or>10,000 sf in redevelopment of more than Pending Draft:within the size, change in >1 acre >1 acre sensitive areas,for new 50%of site or that increases HVRA Overlay, create>10,000 imperviousness,and% impervious impervious by more than 50%, sq ft new impervious area disturbance Tear downs: Create>1 acre applies to entire site; less than impervious or>10,000 sf in 50%of site, applies only to sensitive areas,for all disturbed area/new impervious created by project; impervious Redevelopments that reduce imperviousness by 10%are exempt from rate,volume, and WQ reqs Threshold: non-residential Unknown Disturb>1 acre of land,or Disturb>1 acre of land, or Additions:Create>1 acre Same as above, except where Disturb>1 acre of land >1 acre; requirements vary of redevelopment part of common development part of common development impervious or>10,000 sf in redevelopment of more than Pending Draft:within the <or>40%site disturbance >1 acre >1 acre sensitive areas,for new 50%of site or that increases HVRA Overlay, create>10,000 impervious impervious by more than 50%, sq ft new impervious area Tear downs: Create>1 acre applies to entire site; less than impervious or>10,000 sf in 50%of site, applies only to sensitive areas,for all disturbed area/new impervious created by project; impervious Redevelopments that reduce imperviousness by 10%are exempt from rate,volume, and WQ reqs 1 Development and Redevelopment Project Review/Permit Requirements of Various Agencies REVISED 9/12/2017 Carver County WMO Riley-Purgatory—Bluff Cr WD Lower Minnesota River WD Minnehaha Creek WD Standard Chanhassen NPDES General Permit NPDES Construction Permit Plan:October 26,2010 Plan:January 26,2011 Plan: December 14,2011 Plan:July 5,2007 Rules: 10/15/16 Rules: Effective 1/1/15 Rules:Cities;new standards Rules:6/6/14 pending 9/17 Threshold:grading and erosion Disturb>5,000 sf, excavate or Disturb>1 acre of land,or Disturb>1 acre of land, or >1 acre construction activity; a. Land-disturbing activities As required by the General All land disturbing activity control place>50 cy fill, any part of common development part of common development <1 acres in sensitive areas or that will disturb 50 cubic yards Permit for Construction except agriculture and disturbance on "highly >1 acre >1 acre part of common development or more of earth, Pending Draft: Disturb>1 acre disturbances of less than erodible" land or land in the b. Land-disturbing activities of land, or within the HVRA 5,000 sq ft moving less than Bluff Creek Overlay District, or that will disturb 5,000 square Overlay District,disturb more 50 cu yd with any earthwork permit feet or more of surface area than 5,000 sq feet or disturb or vegetation 50 cubic yards or more of earth, Water quality: new Whichever is most restrictive: No net increase in TP or TSS Wet pond with 1,800 cu ft 90%removal of TP and TSS Provide for at least 60% Treatment as required by the No net increase in TP, except development meet NPDES construction annual load dead storage per contributing from the 1.05"event removal of TP and 90% General Permit for where land use was row permit; NURP criteria (90% acre and live storage of 1"of removal of TSS from all runoff Construction; NURP pond crop/feedlot, must be TSS and 60%;or special runoff from new impervious from site designs apply modeled as if meadow requirements for discharges surface Draft pending:No net to"Preserve"waters increase in TP or TSS.Within HVRA 60%decrease in TP and 80%TSS from predevelopment condition Water quality: redevelopment Whichever is most restrictive: Decrease in TP and TSS annual Wet pond with 1,800 cu ft 90%removal of TP and TSS Provide for at least 60% Treatment as required by the Varies based on size and meet NPDES construction load dead storage per contributing from the 1.0"event removal of TP and 90% General Permit for whether impervious is permit; NURP criteria (90% acre and live storage of 1"of removal of TSS from all runoff Construction; NURP pond increased or decreased TSS and 60%;or special runoff from new impervious from site designs apply requirements for discharges surface Draft pending: No net to"Preserve"waters increase in TP or TSS.Within HVRA decrease in TP and TSS from predevelopment condition _ Rate control No increase over 1-or 2-, 10-, No specific requirement No more than 5.66 cfs per No increase over 2-, 10-,and No increase over 2-, 10-, and No increase over 1-or 2-, 10-, No increase over 1-, 10-, and and 100-year rates acre pond surface area 100-year rates and 10-day 100-year Atlas 14 Nested or 100-year rates Pending 100-year rates, except where snowmelt; Distribution rates draft:using Atlas 14 Nested land use was row Extended detention for sites Distribution rates crop/feedlot, must be discharging directly to modeled as if meadow streams: 50%reduction of 2- year discharge from existing Infiltration: new development Discharging to special waters: No net increase in annual If more than 1 acre of new Abstraction of 1.0" runoff 1.1"abstraction from all 0.5" runoff from new 1"from impervious surface. Infiltration of excess volume runoff volume impervious, infiltrate/abstract from impervious surface impervious surface impervious surface Where 1" infeasible, must do over pre-development 1"from new impervious Pending Draft:sites that at least 0.5" plus additional TP volume, up to 2-yr, 24-hour surface create>1 acre new reduction event Any grading permit:Soil impervious abstract 1"from all impervious.Within HVRA, amendment ripped into sites that create>10,000 sf existing soil materials to a new impervious abstract 1.1" depth of ten inches on the site 2 Development and Redevelopment Project Review/Permit Requirements of Various Agencies REVISED 9/12/2017 Carver County WMO Riley-Purgatory—Bluff Cr WD Lower Minnesota River WD Minnehaha Creek WD Standard Chanhassen NPDES General Permit NPDES Construction Permit Plan:October 26,2010 Plan:January 26,2011 Plan: December 14,2011 Plan:July 5,2007 Rules: 10/15/16 Rules: Effective 1/1/15 Rules:Cities; new standards Rules:6/6/14 pending 9/17 Infiltration: redevelopment Discharging to special waters: Decrease in annual runoff If more than 1 acre of new Abstraction of 1" runoff from 1.1"abstraction from all 0.5" runoff from new 1"from impervious surface. Infiltration of excess volume volume impervious, infiltrate/abstract impervious surface impervious surface impervious surface Where 1" infeasible, must do over pre-development 1"from new impervious Pending Draft:sites that at least 0.5" plus additional TP volume, up to 2-yr, 24-hour surface create>1 acre new reduction event Any grading permit:Soil impervious abstract 1"from all impervious. Within HVRA, amendment ripped into sites that create>10,000 sf existing soil materials to a new impervious abstract 1.1" depth of ten inches on the site Wetland buffer 16.5 to 50 feet from wetlands No specific requirement 100 feet from a special water Minimum 20 feet, adjusted Avg width 20 to 80 feet from a.<2 acres, 25' minimum; 16 to 75 feet, depending on depending on mgmt. class; based on slope,whether wetlands, depending on b. .2 acres, 25' minimum, wetland mgmt class 100 feet from special water runoffs directed to the buffer mgmt.class; 50 feet from a average 50' or if the wetland is ranked water basin;50 feet from the "high,"to a maximum 50 feet thalweg of any watercourse in a High Risk Erosion Area, 50 feet from the centerline of a public waters watercourse Linear projects No specific requirement Disturb>1 acre of land; may Disturb>1 acre of land Projects adding 1 acre or If project constructs more No specific requirement Projects creating>10,000 sq ft be excepted from some or all more of impervious(10,000 sf than 5,000 square feet of new impervious surface infiltration requirement if lack in sensitive areas),for new impervious,and creates>_1 sufficient right of way impervious created by project. acre new or fully Reconstructs that reduce reconstructed impervious imperviousness by 10%are surface.Applies only to all exempt from rate,volume, new and reconstructed and WQ reqs impervious surface. Bluff requirements No removal of vegetation and No specific requirement No specific requirement Unknown Unknown No removal of vegetation in No specific requirement no new impervious in the the Bluff Impact Zone and Bluff Impact Zone(20'from Bluff Face; new structure top of bluff); new structure setback 30 ft top of bluff,SSTS setback 30 ft top of bluff,SSTS setback 50 ft. Pending Draft: setback 50 ft establishes High Value Resources Area (HVRA) Overlay District. New definition of Bluff 18%slope TP-40 or Atlas 14 TP-40 No specific requirement No specific requirement Atlas 14 Atlas 14 Cities Will adopt Atlas 14 as part of Pending Draft:Atlas 14 current rule revision 3 Land and Water Resources Inventory (This page is intentionally blank.) Table of Contents 1.0 Physical Inventory 1-7 1.1 Physical Environment 1-7 1.1.1 Climate and Precipitation 1-9 1.1.2 Geology,Topography and Drainage 1-9 1.1.3 Soils 1-11 1.2 Biological Environment 1-13 1.2.1 Vegetation 1-13 1.2.2 Fish 1-13 1.2.3 Unique Features and Scenic Areas 1-14 1.3 Human Environment 1-16 1.3.1 Land Use 1-16 1.3.2 Future Land Use 1-16 1.3.3 Parks, Open Space, Recreational Facilities 1-19 1.3.4 Pollutant Sources 1-19 2.0 Water Resources Inventory 2-1 2.1.1 Watersheds 2-1 2.1.2 Lakes 2-3 2.1.3 Streams 2-3 2.1.4 Wetlands 2-1 2.1.5 Public Waters 2-2 2.1.6 Special Waters 2-2 2.1.7 Groundwater 2-5 2.1.8 Floodplain 2-5 3.0 Subwatershed Summaries 3-1 3.1 Lotus Lake Subwatershed 3-3 3.1.1 Subwatershed Characteristics 3-3 3.1.2 Issues &Opportunities 3-4 3.2 Lake Minnewashta Subwatershed 3-5 3.2.1 Subwatershed Characteristics 3-5 3.2.2 Issues & Opportunities 3-5 3.3 Lake Lucy Subwatershed 3-7 3.3.1 Subwatershed Characteristics 3-7 3.3.2 Issues & Opportunities 3-8 3.4 Lake Ann Subwatershed 3-9 3.4.1 Subwatershed Characteristics 3-9 3.4.2 Issues & Opportunities 3-10 3.5 Lake Susan Subwatershed 3-11 3.5.1 Subwatershed Characteristics 3-11 3.5.2 Issues & Opportunities 3-11 3.6 Rice Marsh Lake Subwatershed 3-13 3.6.1 Subwatershed Characteristics 3-13 3.6.2 Issues & Opportunities 3-13 3.7 Lake Riley Subwatershed 3-15 3.7.1 Subwatershed Characteristics 3-15 3.7.2 Issues & Opportunities 3-15 3.8 Bluff Creek Subwatershed 3-17 3.8.1 Subwatershed Characteristics 3-17 3.8.2 Issues & Opportunities 3-17 3.9 Lower Minnesota Subwatershed 3-19 3.9.1 Subwatershed Characteristics 3-19 3.9.2 Issues & Opportunities 3-20 3.10 Drainage to Neighboring Communities 3-21 3.10.1 Subwatershed Characteristics 3-21 3.10.2 Issues & Opportunities 3-22 4.0 References 4-1 Figures Figure 1.1. City of Chanhassen location map. 1-10 Figure 1.2. Hydrologic Soil Groups (HSG) in Chanhassen. 1-12 Figure 1.3. Unique features in Chanhassen 1-15 Figure 1.4. Chanhassen 2010 land use and 2020 MUSA limits. 1-17 Figure 1.5. City of Chanhassen 2030 land use 1-18 Figure 2.1. Watershed Management Organizations in Chanhassen 2-2 Figure 2.2. Lakes and streams in Chanhassen 2-4 Figure 2.3. Chanhassen wetlands on the National Wetlands Inventory. 2-3 Figure 2.5. Chanhassen lakes and streams on the DNR Public Waters Inventory. 2-4 Figure 2.6. FEMA floodplain in Chanhassen. 2-6 Figure 3.1. Chanhassen modeled subwatersheds 3-2 Figure 3.2.The Lotus Lake subwatershed. 3-3 Figure 3.3. Lake Minnewashta subwatershed 3-6 Figure 3.4. Lake Lucy subwatershed. 3-7 Figure 3.5. Lake Ann subwatershed. 3-9 Figure 3.6. Lake Susan subwatershed. 3-12 Figure 3.7. Rice Marsh Lake subwatershed 3-14 Figure 3.8. Lake Riley subwatershed. 3-16 Figure 3.9. Bluff Creek subwatershed. 3-18 Figure 3.10. Lower Minnesota River subwatershed 3-19 Figure 3.11. Drainage to neighboring communities 3-21 Tables Table 1.1. Climate and precipitation data at Chanhassen, 1981-2010. 1-9 Table 1.2. 2010 land use in the City of Chanhassen 1-16 Table 2.1. Watershed Management Organizations within Chanhassen 2-1 Table 2.2. Water quality standards for lakes in the North Central Hardwood Forest Ecoregion. 2-3 Table 2.3. Characteristics of lakes in Chanhassen, 2007-2016. 2-3 Table 2.4. Characteristics of streams in the City of Chanhassen. 2-3 Table 2.5. NWI wetland area by type in the City of Chanhassen. 2-1 Table 3.1. Chanhassen modeled subwatersheds. 3-1 Table 3.2. Lotus Lake subwatershed 2010 land use 3-4 Table 3.3. Lake Minnewashta subwatershed 2010 land use. 3-5 Table 3.4. Lake Lucy subwatershed 2010 land use. 3-8 Table 3.5. Lake Ann subwatershed 2010 land use. 3-9 Table 3.6. Lake Susan subwatershed 2010 land use. 3-11 Table 3.7. Rice Marsh Lake subwatershed 2010 land use 3-13 Table 3.8. Lake Riley subwatershed 2010 land use 3-15 Table 3.9. Bluff Creek subwatershed 2010 land use. 3-17 Table 3.10. Lower Minnesota River subwatershed 2010 land use. 3-20 (This page left intentionally blank) I 1.0 Physical Inventory 1.1 PHYSICAL ENVIRONMENT The City of Chanhassen lies in the northeastern corner of Carver County (Figure 1.1Error! Reference source not found. Page I 1-7 Appendix A Land and Water Resources Inventory Shorewood �• i • �u�u=■ .Mn=u�n�o.n...=a=n�u�•11.Mu�uMu=n=u�u�n=u . 1 1 I H 1 1' i i L 1 l I 11 i ; ._$1 1 Chanhassen 1••° 1 Ar••tetum Blvd 2 v; 76!it SI i i 'OW tar Blvd dPammusimai S01•11111111.1=11111111.111•11 1 • ,.1%.N.0.0.00 0, ; i FS�,_;P H_ Lake. _ Bt/S 3n d' Ly h,..i'''.i'.1 .. 'O 2. J' '�� 1 on 0 a. Upne �0�: 0 1 t La.a 11,E � ,ia 1 f 1 i 1 1 i i 1 1 1 i ' '`.. i i n., 1 i 1 i I i 1 \--.... i i i I i Anoka S �. y a..�..m:.m..m..m..i 1 i �,,�. 1 st�'' Hennepin w shind on aD h‘' �•. ., .1 Shakopee F�amse 0 too. .,, .�� 1 1 l� ' •,..0„.„.4 .•t mew ,1h r'-4, N y " Carver 111_,_,,..,,,) L_ f� C�.�-\.1 WI Ave t' ",r Scott _ Dakota _1 1 0.5 0 1 ►_ 1 Miles ), within the Minneapolis-St. Paul Metropolitan Area. The city encompasses 22.9 square miles and is Page I 1-8 Appendix A Land and Water Resources Inventory bordered by Chaska to the west,Shorewood to the north, Eden Prairie to the east, and the Minnesota River to the south. A small part of the City extends into Hennepin County. 1.1.1 Climate and Precipitation The climate is humid continental with moderate precipitation, wide daily temperature variations, warm humid summers, and cold winters. The total average annual precipitation is approximately 31.2 inches (Table 1.1) while the annual snowfall average is approximately 54 inches, equivalent to approximately 5.4 inches of water precipitation. Table 1.1. Climate and precipitation data at Chanhassen, 1981-2010. Average Average Average Precipitation Snowfall Month Temperature(°F) (inches) (inches) January 14.3 0.87 10.3 February 19.1 0.94 9.7 March 31.3 1.78 10.8 April 46.5 3.00 3.4 May 58.0 3.66 0.0 June 67.6 4.02 0.0 July 72.0 3.59 0.0 August 69.9 4.14 0.0 September 60.7 3.43 0.0 October 47.8 2.51 0.4 November 32.7 1.97 5.4 December 18.1 1.25 13.9 Annual Average 44.8 31.16 53.9 Source: NOAA National Climatic Data Center. 1.1.2 Geology,Topography and Drainage The landscape of Chanhassen was shaped by the Des Moines lobe of the Wisconsin glaciation.The bedrock underlying Chanhassen is primarily Prairie du Chien Group dolostone, with Jordan sandstone underlying a bedrock valley along the western side of the city and Lone Rock Formation in the Minnesota River Valley(Mossier and Chandler 2009). The surficial geology is primarily glacial till - pebbly, unsorted, with scattered cobbles and rare boulders-with scattered deposits of organic debris and marl. Outwash and floodplain alluvium is found in the River valley. Refer to the Carver County Geologic Atlas for more information. Page I 1-9 Appendix A Land and Water Resources Inventory Shorewood ''i , �.wu_n—u-n-u-u_.._n_n_u_u1•u_..—n_u-1�._u_u_u_n_u_u_.._u_u_u_u_u_..n •# j 1. -un '.' ra i 1 h • i 11 yl Lucy Rd 'fid 111 1 p11 1 1 • I-•. -dI r.:i f..I, i Le.e H LOtc, Lucy §d trtRe 1 m 1 m i 410 1 1• i i i 40••1 Rrt •return EiVd Chanhxsen j, j W 78th Si i Couitm eivd rismnammill '• allENIIMONIMIMINI1111111 A14, I Z c' ell i.� ♦ j c / i i 1 i I i 1 i i j i 1.,t i j ,, ! i 1 fr "\-....-.\., 1 6 1 4G 1 1 1 i i ` 1 1 Or .•I w1n0G r. Anoka ,• aoMn�nMIn �n=na i ) i �� i i,rA Washin�jon 1 Hennepin ,a t.k° o••� 'N I Shakopee (jamsey c=' o.• ., e`\N �� ..o``l� ,,r,Pv a i- N w Carver�.._� 'i i ,' s'"7- (-�—`1 rth Pva'' :n S 1-1..-7-.Scott 7 Dakota (r 1 1 0.5 0 1 .. __I--) ....."11 ' Miles Figure 1.1. City of Chanhassen location map. Source: Minnesota DNR,World Street Map Page I 1-10 Appendix A Land and Water Resources Inventory The landscape is characterized by four geomorphic units.The central part of the city is located within the Prior Lake Moraine unit, which consists of irregular ground, end and terminal moraines, and ice disintegration features of loamy texture.The dominant landform is rolling hills and irregularly placed knolls with relief ranging from 20 to 100 feet above the base,with wetlands in deeply inset depressions. The northwest area of the city,west of Lakes Ann and Lucy and including Lake Minnewashta and the Arboretum is within the Emmons-Faribault Moraine, and the topography is typical of that region— gentle rolling hills with an abundance of lakes and ponds. The northeast portion of the city, including the areas around Lotus Lake and Rice Marsh Lake, are within the Twin Cities Formation geomorphic unit. The landscape of the Twin Cities Formation is similar to the Prior Lake Moraine unit—steeply and irregularly rolling—but it is underlain with a silty, clayey,glacial till. In the southern part of the city, the Minnesota Valley Outwash Plain is nearly level with low terraces, and comprised of areas of sand and gravel. 1.1.3 Soils The soils in Chanhassen are generally moderate to well drained Lester and Kilkenny clay loarns with pockets of moderately to poorly drained soils. In the Minnesota River Valley, floodplain soils are generally muck or silt foams and range from moderately to very poorly drained. Refer to the Carver County Soil Survey for more information. Soils are classified by the Natural Resources Conservation Service (NRCS) into hydrologic soil groups (HSGs) to indicate the minimum rate of infiltration obtained for bare soil after prolonged wetting.The HSGs are A, B, C and D. Figure displays the hydrologic characteristics of soils in Chanhassen.Type B soils predominate, but there are many pockets of B/D and C/D soils. These dual-designation soils tend to follow the terrain and characterize the lower areas. A Sandy soils with low runoff potential.These soils have a high rate of infiltration even when thoroughly wet.They are deep,well to excessively drained sands or gravels. B Loamy soils with a moderate infiltration and transmission rate when thoroughly wetted and with moderately fine to moderately coarse textures. Water movement through these soils is moderately rapid. C Sandy clay loam soils with a slow rate of infiltration rate when thoroughly wet. Water movement through these soils is moderate or moderately slow and they generally have a restrictive layer that impedes the downward movement of water. D Clayey soils with very slow infiltration rates because of clay content, high water table, or claypan or clay layer at or near the surface. These soils have a very slow rate of water transmission. A/D Dual hydrologic soil groups are given for certain wet soils that could be adequately drained.The B/D first letter applies to the drained and the second to the undrained condition. Soils are assigned to C/D dual groups if the depth to a permanent water table is the sole criteria for assigning a soil to hydrologic group D. Source: Natural Resources Conservation Service. Page I 1-11 Appendix A Land and Water Resources Inventory -- 11‘4,;4110 - -11-1cAr, . mih.. -tap: r- • 11 '-.7 •- tj te •Nri)t.- :r..-..dp„,• vo tilt W1V -V ri : .2'. Lake Qr 1♦ i� M Minnewashta (— ,` I 1` 4 i\� /\ !� Lake` 117i , .) ��0 irl,\i� Lotus , • 1 .e . / Lake Lake �v. Lake i -._� ��Har�ison Lucy / �I, St.Joe (/ + �` ;✓ ` z , y _ �( ;� 41 d 1 f • ' Lake r4��.4` . f�CI s i*--' ! r `,.,• .��. • . ,,., • .i , i • _• - 49. 1E4,-e7 & F rr 11 WI -I—:I..a7-*-,---4 p4. 1 *' IM o . . „9. /i.A1..1..I4.W ; r -4-.:'7.q1'.. vii .:s. K0 j ,r fake 4 �1 1 1 rr!�2`� ►�1 Susan ` Rice Mara / . A4 . ,141 �� j � �i ` 441Lake \ 417 w � • ✓ .�1 1 17 �� C EP t I Hydrologic Soil Group `�,\ %,' Rake A- Sandy y � j £ 4 .•, i A/D , - .41 t�ki B - Loamy —41... r 1a B/D A i - 1 61 - 7 1 Rice iSt*Ston Lake Pssx p n ,. I A t 1 �c 1 N iaFR� M`o�so 1 0.5 0 1 mii i. Miles Figure 1.2. Hydrologic Soil Groups (HSG) in Chanhassen. Source: NRCS, SSURGO. Page I 1-12 Appendix A Land and Water Resources Inventory 1.2 BIOLOGICAL ENVIRONMENT 1.2.1 Vegetation The City's landscape has gone through many changes due to human activity. Prior to European settlement the landscape across much of the central part of the city was "oak openings." Today oak openings are called oak savanna, a now-rare in Minnesota landscape that is transitional between prairie and forest. Savannas are grasslands with scattered trees providing between 30 percent and 70 percent canopy cover, and are maintained by fire. Bur oaks and a few other tree species typical of oak savannas are fire resistant. When a fire swept through a savanna area, the maples, basswood, and other fire- susceptible species burned but the oaks remained and the prairie species were rejuvenated. Most of the rest of the city was Big Woods, where oak woodland and maple-basswood forests were the dominant vegetation types. Upon settlement, much of the landscape was converted to agriculture and eventually suburban development. However, there are remnants of the original landscape, as well as patches of only moderately impacted lands that retain some higher ecological values. The Minnesota County Biological Survey(MCBS) has identified those locations in the Metro area with intact native plant communities, and those with biodiversity significance. The ecological value of these Regionally Significant Terrestrial and Wetland Ecological Areas is determined by examining attributes of the patches including size, shape, cover type diversity, and adjacent land use. Three areas of outstanding ecological value have been identified in Chanhassen: Seminary Fen; Rice Marsh Lake and its riparian wetland; and the Minnesota River corridor. The Minnesota River Valley is home to significant natural communities, including remnants of the Big Woods, river bluffs,and wetland areas.Additional areas identified as having high ecological value include patches within the Landscape Arboretum; the Lower Bluff Creek corridor; and patches in Lake Minnewashta Regional Park. Other small patches around Lake St.Joe and Lake Ann and in the Arboretum were classified as moderate ecological value. Most of the significant natural communities identified in the Carver County Biological Survey are in areas under public ownership and have been preserved as park or managed conservation areas. 1.2.2 Fish Two boat lunches on Lake Minnewashta provide public access to the lake for fishing and boating. There is also a fishing pier at Roundhouse Park, which is extended to reach beyond the aquatic plant edge.The most recent fish survey, completed in 2011, found abundant northern pike and largemouth bass, and six species of panfish. Rough fish are present but in low numbers. The DNR has imposed a catch and release limitation on largemouth bass. A fishing pier and boat launch are available on Lake Ann at Lake Ann Community Park. Each year on the first Saturday in February,the City hosts February Festival on Lake Ann. One of the highlights of this community event is an ice fishing contest. The Minnesota DNR completed a detailed fish survey and assessment on Lake Ann in 2012.The DNR is actively managing the fishery, having imposed both a catch and release limitation on largemouth bass and a size restriction on northern pike.The survey found that these regulations appear to be helping to restore the size structure for those communities.The 2012 assessment also included an evaluation of fish in the shallow, nearshore habitats to calculate an Index of Biotic Integrity score. Sensitive species such as minnows and darters were mostly absent, contributing to a low IBI score. In August 2012,Ann Page I 1-13 Appendix A Land and Water Resources Inventory Lake scored 74.6 out of a maximum of 160, indicating possible water quality and habitat impairment. In September 2012,the nearshore survey was replicated and the second score was 76.4, very similar to the first.There are special regulations limiting human consumption of fish from Lake Ann. A fishing pier and boat launch are available on Lake Susan at Lake Susan Community Park.The 2009 Lake Susan DNR fish survey found that fish abundances were low, as historically been the case.There are special regulations limiting human consumption of fish from Lake Susan. The University of Minnesota is conducting research on common carp in Lake Susan. The goal of carp research in Lake Susan is to determine the relationship between carp abundance (biomass) and 'lake health' measured as water quality, vegetation density and native fish. To do so, specific numbers of carp are removed from each lake while improvements in water quality,vegetation, and native fish are monitored. In 2009, carp biomass in the lake was reduced from about 300 lbs/acre to about 60 lbs/acre.After the carp were removed, aquatic vegetation coverage increased from 5 percent of the lake to 45 percent. Spring water clarity was greatly increased, but there appears to be minimal impact on summer clarity and total phosphorus concentration. Lotus is primarily managed for walleye and largemouth bass, with walleye fingerling and adult fish stocking every other year.There are special regulations limiting human consumption of fish from Lotus Lake. 1.2.3 Unique Features and Scenic Areas Seminary Fen, a DNR Scientific and Natural Area (SNA), lies to the north of Flying Cloud Drive, west of Bluff Creek Drive (Figure 1.3). Named for an old seminary that was once on the site, Seminary Fen contains one of the rarest types of wetland in the United States, a calcareous fen. Calcareous fens are a special type of wetland that can occur only at the base of slopes or bluffs, where cool, mineral-rich groundwater appears as springs. Water charged with minerals comes to the surface, then saturates and helps maintain thick layers of peat created by the decomposition of the plants that grow in the oxygen- poor water. Fewer than five hundred calcareous fens survive in the world. It is home to many threatened and endangered plant species. Calcareous fens have special protection under Minnesota state law and may not be drained, filled or otherwise altered or degraded. A history of Seminary Fen may be found at mnopedia.org/place/seminary-fen-scientific-and-natural-area. Seminary Fen's groundwater drains into Assumption Creek, one of the few trout streams in the Metro Area. South of Flying Cloud Drive and west of TH 101, in the floodplain of the Minnesota is the DNR's Raguet Wildlife Management Area (WMA). Wildlife viewing and hunting are allowed in this WMA. Portions of the city south of Flying Cloud Drive are located in the Minnesota River Valley National Wildlife Refuge. Page I 1-14 Appendix A Land and Water Resources Inventory it �e 1 ■�lin � � - ©_ _ _ 82 Christmas itral' 'moo maul will 7 Lake• :77 4."4.. . ....2 0 .. diir iiiii 1,414Lizalisil Lake . _ �� 1 htinnewashta Lake.11ianenashta I \� ` Lotus 1.1 I Regional Porn Lake 117,11' Lake �� `� Lake Lake T Harrison Lucy �' �� hil if`St Joe �T 4._*„ Alriti Lake = . 1/4eir Ann �� f -)© , iiiin �: 1111 0'- .••' u vinncsota * r I tl�� Landscape00119 1 VI ....tr., i .Irhorenan �.` �� i � mil 11....4r./....„ ...: Ili , 1ins Lake Rice hlarJ LSusan ,li Lake , ..., --:,- Ali . .; ,.. warm) , ! i 117 i T Riley ipLake PIII)/i.C)'% 4 sit. j 14 1 1 ! i 1 ' I . 81 1 Seminars.1 len . Rice! ` ti\on cr Lake. Regional Parks f - =>.11innesota fuller , Rapier'Ii'•1f I National-If -4.-E-efr'ge'i Park, Recreation, Open Space ' Vt.� Scientific and Natural Areas i ,••��•0' M�Opea0 eI 1111< N Wildlife Management Areas t" ---w-- Trout Streams • Fens 1 0.5 0 1 i Miles Figure 1.3. Unique features in Chanhassen. Source: MnDNR. Page I 1-15 Appendix A Land and Water Resources Inventory 1.3 HUMAN ENVIRONMENT 1.3.1 Land Use Figure 1.4 shows existing land use within Chanhassen.The city is over 80%developed, and has a commercial and industrial core centered on TH 5, surrounded by residential uses of various densities. According to the City's Available Land inventory, only about 3%of vacant land in the city is developable. Regional and local parks and open space, including Lake Minnewashta Regional Park,the University of Minnesota Landscape Arboretum, encompassing over one-fifth of the city's area. Only the Minnesota Valley Wildlife Refuge and areas within the Minnesota River Bluffs in the southern part of the city are outside the Metropolitan Urban Services Area (MUSA). Table 1.2. 2010 land use in the City of Chanhassen. Area Area Land Use (acres) (%) Single Family 4,297.64 29.3% Parks and Recreation 2,988.71 20.4% Undeveloped 2,923.22 19.9% Water 1,712.82 11.7% Agricultural 1,116.35 7.6% Industrial 486.28 3.3% Commercial 390.61 2.7% Highway 369.93 2.5% Institutional 275.53 1.9% Multi Family 54.48 0.4% Extractive 43.75 0.3% 14,659.31 Source: Metropolitan Council from city comprehensive plan and air photos. 1.3.2 Future Land Use Planned 2030 land use from the 2009 Comprehensive Guide Plan is shown in Figure 1.5. The southernmost'part of the City south to Flying Cloud Drive is within the MUSA 2020 boundary, and is expected to be in development by that time.Some large-lot residential development relies on individual subsurface sewage treatment systems, and will continue to do so until the majority of residents in an area desire to hook up to city sewer and water.The area south of Flying Cloud Drive to the Minnesota River is currently unsewered, and there are no plans to extend urban services to that zone. Page 1-16 Appendix A Land and Water Resources Inventory 1[ I 64/ t 1 MI 4/4 lir* 411%* 110' 1" 8-2 , ..... !... aim I I ifttor :!:iira % F ...It 1 401., ii li as .40 4 MP si ' Lake . e 011 1 Minnewashta "` Lotus 117 !�� .' �►-'. Lake ifil ....,- Lake i Lake Lucy 1 �y bp St.Joe ti It 4f Lake;.. iIfi. Al fit 1 : fil el 1, 1 ... 44, El Awl" i. l VP a I 19 N,;� 1 ' it amaimms MI \WisWO s i1r ll , 78 ,k Lake i.i ` Susan , a Rice Marsh Lake ----- i ss 1 'I el- 1111 A `e- is, 1741IP 4-j 1 .a. j All I 1 2010 Land Use Single Family W � ` 1171 e< , - Rile Multifamily �� r Lake 1111 Commercial II /` Industrial 411 /4.1‘11161 ��40 lL Extractive ` Institutional _ ; / ��; �`` - - Park, Recreation, Open Space ��4( � �,, /l - Transportation N � � �I�� I A,/ ��il Agricultural / Aloft �/. - , t� x,81 , Undeveloped ��5u�.p"Orl'er `�' Water �`►�I/ !ea MUSA 2020 , )—P ® Unsewered • va N be o 1 0.5 0 1 i Miles Figure 1.4. Chanhassen 2010 land use and 2020 MUSA limits. Source: Metropolitan Council,from city Comprehensive Plans and air photo interpretation Page I 1-17 Appendix A Land and Water Resources Inventory . •—• 4.- - ir,,..N. .1.---.--- dIEPA'l i.i i••:',% '.. l• ill ' i 'f-t.Z-1-W-"4, r:A.,"“E• •''.4....'"..50G ,.a3 t.PI l' ligthl.,_. ' '11i7:• :•.•'a...i. ;# •AMOY-,..-:;: " ' _LI ..;iril1i '..9141;;Vj '!_pu•141EILit'Aill'?..1%' .. a' a,c;?: r ' .•41:-...• ' lti";.,'. ' - . ' :vitae;.- •- :nr•makU.:,;..,/_.."5..,m..4. i3.r.„; , , ,..,_,..40,- ., .0,a, •..--"welirmihs•:.,t,.40.i.-...- •r..../,, 0,,,- , •a . .`, •IIAAI-":1•1-isrl. '- ' Q. -' ... !•..-17.''..••! ta ,A N.,' - - 4.7r. -•-il:: ;'.-;:: 4,v--;- / 'l "74.1:-. .- ... •,* 1. .t...... .• , .-.--,7,..„--sx. .1"...- ./..•-.-.•...,:li.,! i %.,,,,,..,.,v•.:::.. -.- - lot '.••••••••••_,.--.-;;..41.. .7 .. t• II, , .u4,,,,: i!.4. dt.: - . -_: 1..1.4.'ea1c-0•1111.1 1,,‘,j' ",e`.... .."...2- ".. li ".•• .., .t. ....','-' •Fe lc. .17‘. ..a W111`MA '.• 'r'a ,;:li ,Y,-..,'0. - • ....... -, ,,,...v.. „_,..,,,:,,.&-,-_-,• ...,..... .... _ r ,. , - 1:1°: i ,,-. iit.„,._._ ,... ,,,,j-Pos ....:4,-. • _, t •.-. •,.._..-. ,...0•,'-•- t..i.L... aligp. A— VS ' •:•:4:: i iiiti" ''. en mi 4.,.. ..r..9. ", .... 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Oie•- 7 tip di 1 WW1& I 1 001.WERICAL ,,' ii - •- sinlitm, 4....4 • 1 "T , ' likvqini aititAijil-, gi OFFICE - .11, ab. *4.1oll Oh. 10 111.1 . 4 -'''.6- ikl HI ill OFFICE BNOLMTRAL '40. \ Al -- ,. up GIN, $1111",,, 171, ill MIXED , . . . .... , ED RESIDENTAL LARGE LOT irk. 044 r4111A41(A)P - - .1,- mi. ..........,iip. j ....-- ;II ifl RESIDENTIAL Loyo DENSITY Deones,n,MO I%IP;1411 W qiii rir .E ti' NW ill RESIDENTIAL MEIYUM DEN3Irr 1110 4..ill1,\ - iik 6. 1.4 j -- Fri RESIDENTIAL HIGH DENIIITY ir.,,Ivemilami,..--400.11. [rj AGRICULTURE IIII AM Fri PAWS OPEN Fri PUBLIC SEP.%PLeuc klik - — 411111iia Illi- BLUFF CREEK PRIWAY CORRIDOR POTWIAL SiPPORT CCUPAERCAL P 'I Wwwwwl Wn Figure 1.5. City of Chanhassen 2030 land use. Source: City of Chanhassen 2030 Comprehensive Plan Page I 1-18 Appendix A Land and Water Resources Inventory I 1.3.3 Parks, Open Space, Recreational Facilities Three regional parks and recreation facilities are located in Chanhassen: Carver County's Lake Minnewashta Regional Park,the Minnesota Landscape Arboretum, operated by the University of Minnesota, and the Three Rivers Park District Minnesota River Bluffs LRT Regional Trail, which passes through southern Chanhassen, crossing Bluff Creek and running north of Seminary Fen. Swimming beaches are available Lake Minnewashta Regional Park, and city parks Lake Ann Park, Carver Beach on Lotus Lake, and Roundhouse Park on Lake Minnewashta. 1.3.4 Pollutant Sources The Wellhead Protection Plan (WHPP) completed in 2004 evaluated and included recommendations for monitoring or remediating potential pollutant sources such as dumpsites, leaking underground storage tank sites,Voluntary Investigation and Cleanup sites and others. Information on these sources can also be found by contacting the Minnesota Pollution Control Agency or the Environmental Protection Agency, or visiting the EPA's EnviroMapper website at www.epa.gov. Subsurface sewage treatment systems(SSTS), or septic systems, and operating or abandoned wells can also be a source of pollution. Chanhassen had an estimated 351 septic systems in 2004. The MDH regulates new and abandoned wells and maintains a comprehensive list of the status of each. A plan for management of private wells and septic systems is also included in the City's WHPP. Page I 1-19 Appendix A Land and Water Resources Inventory 2.0 Water Resources Inventory 2.1.1 Watersheds The Twin Cities Metropolitan Area is subdivided into about 34 watersheds, each managed by a Watershed Management Organization (WMO). WMOs may be either Joint Powers consortia of cities or Watershed Districts, which are special units of government. Chanhassen is located in four watersheds (Table 2.1 and Figure 2.1), three of which are Watershed Districts,and one a Joint Powers Organization. Table 2.1. Watershed Management Organizations within Chanhassen. Area in Total Area Percent of Watershed Chanhassen (sq.miles) Chanhassen (sq. miles) Riley-Purgatory-Bluff Creek WD 47.1 14.0 61.3% Minnehaha Creek WD 180.1 5.2 22.8 Lower Minnesota River WD 75.9 2.9 12.7 Carver County WMO 320.2 0.75 3.2 TOTAL 22.85 100% 2.1.1.1 Riley-Purgatory-Bluff Creek Watershed District The RPBCWD covers approximately 32.8 square miles in Hennepin County and approximately 14.3 square miles in Carver County. Nearly two-thirds of Chanhassen is within the RPBCWD, including six lakes— Lucy, Ann, Susan, Lotus, and part of Riley and Rice Marsh. Bluff Creek drains the central area of the city south to Rice Lake. Riley Creek is formed at the outlet of Lake Ann and flows to Rice Marsh Lake and into Eden Prairie. The northeast corner of the city flows to Lotus Lake, which outlets east into Eden Prairie and Purgatory Creek. 2.1.1.2 Minnehaha Creek Watershed District The Minnehaha Creek Watershed District (MCWD) encompasses 181 square miles in Hennepin and Carver Counties. Almost one-quarter of the city is within the MCWD, including the area west of Hazeltine Boulevard draining to Lake Minnewashta, and an area along the northern border, part of which drains to Christmas Lake and part into Lake Galpin to the north. Lake Minnewashta and Lake St. Joe are in this drainage area, as is a southern bay of Christmas Lake. 2.1.1.3 Lower Minnesota River Watershed District The LMRWD is located in the far southern part of Chanhassen and includes the Flying Could Drive corridor and floodplain to the Minnesota River, and the area east of TH 101 and south of Pioneer Trail to the river. The overall District boundaries encompass an area of 64 square miles of Carver, Hennepin, Dakota, Scott, and Ramsey Counties, including bluffs on both sides of the Minnesota River.The LMRWD includes Rice Lake, Assumption Creek, and Seminary Fen. Page 12-1 Appendix A Land and Water Resources Inventory 2.1.1.4 Carver County WMO A few small areas of Chanhassen are within the Carver WMO. In southwestern Chanhassen, the area west of Bluff Creek Drive, north of Seminary Fen, and south of TH 212 is in the Carver WMO and drains into Chaska.A small corner of Chanhassen west and south of Lyman Boulevard and Galpin Boulevard drains to Lake Hazeltine in Chaska. Nell ...Vit. 44,tolir,•.... . 1 i. ..I .1 MI = i i I am. 7.7.41).1111 v '.�`' akra w1 ''i' i Er Lake i t im.<4 e 13> Ltinnewashta IR P �,� 117 IRi \` Lotus Lake 1 Lucy � � ' Lake �� '' Al St.Joe ■■■■ Lake t{ egill ----- cEl a b Ann j , :• i. hh. 1--- .... I 1----.79 1gi ,- . 1 � r 18 he Lake liviti Susan - - .Rice Marsh .111)1111 Lake. e.g., . ,, � W 'WI, j `117 4 0 03 Riley • 'C;. 17 Lake i 4_ e� 4,114 Watershed Management Organization !' k- 1 i CARVER COUNTY j i LOWER MINNESOTA RIVERI IQ ! MINNEHAHA CREEKI i 212 RILEY-PURGATORY-BLUFF CREEK j sc,oms"on Cr Lake . ! r IPP ' 0it i 11.4" ! yet s P` 1 ivo\no '.r., 1 0.5 0 1 i1 —....—.... Miles Figure 2.1.Watershed Management Organizations in Chanhassen. Source: Board of Water and Soil Resources. Page 12-2 Appendix A Land and Water Resources Inventory 2.1.2 Lakes There are 9 major lakes in Chanhassen, which are shown on Figure 2.2. Minnesota's standards for lake water quality vary depending on the depth classification of the lake (Table 2.2). Shallow lakes are 15 feet deep or less, or 80%or more of the lake area is shallow enough to support rooted aquatic plants.The lake number and shoreland classification, lake morphometry, and water quality data are shown in Table 2.3. More information about the lakes can be found online at the DNR's LakeFinder website: dnr.state.mn.us/lakefind/index.html. Table 2.2. Water quality standards for lakes in the North Central Hardwood Forest Ecoregion. Parameters Shallow Lakes Deep Lakes Total Phosphorus(TP) (µg/L) 5_60 5540 Chlorophyll-a (chl-a)(µg/L) 520 514 Secchi Depth transparency(SD)(meters) >_1.0 >_1.4 Source: MPGA. Table 2.3. Characteristics of lakes in Chanhassen,2007-2016. DNR Surface Max Depth DNR Summer Average Lake ID# Area Depth Class Class* TP Chl-a SD (ac) (ft) (µg/L) (µg/L) (m) Ann 10-0012 116 42 Deep RD 23 9 3 Christmas 27-0137 257 87 Deep RD 13 2 6 Harrison 10-0008 6 Na Shallow NE NA NA NA Lotus 10-0006 246 29 Deep RD 54 36 1 Lucy 10-0007 92 18 Shallow RD 67 21 1 Minnewashta 10-0009 738 70 Deep RD 24 9 2 Rice Marsh 10-0001 79 11 Shallow NE 120 2 2 Rice 27-0132 238 Na Shallow NE NA NA NA Riley 10-0002 297 49 Deep RD 41 21 2 Susan 10-0013 93 17 Shallow RD 119 40 1 St.Joe 10-0011 14 52 Deep NE 25 5 3 Sources:Minnesota DNR,MPCA EQuIS. *NE=Natural Environment;RD= Recreational Development(Shoreland Management Classification) 2.1.3 Streams Bluff Creek is the longest stream in the City (Table 2.4, Figure 2.4), rising from a wetland complex in the northwest quadrant of Highway 5 and Galpin Boulevard,then flowing just over 7 miles southeast to Rice Lake in the Minnesota River floodplain.The headwaters of Riley Creek is Lake Ann. From the lake's outlet Riley Creek flows southeast to Lake Susan, and then outlets Lake Susan to Rice Marsh Lake. On the Eden Prairie side of the lake, the Creek flows out of that lake south to Riley Lake,then outlets that lake and flows to the Minnesota River. Assumption Creek is a DNR-designated trout stream. Table 2.4. Characteristics of streams in the City of Chanhassen. Stream Length(mi) Bluff Creek 7.1 Riley Creek 2.5 Assumption Creek 2.8 Source:MnDNR. Page 12-3 Appendix A Land and Water Resources Inventory Figure 2.2. Lakes and streams in Chanhassen. II y / 1 r -4•11110,11 , f© 82 iii, Christmas FIN . ililior �,� istimi ■� Lake. ■.n urn alodirt ... ., :91. .d.siir dif 60 Lakelip t ftlli►4 it 01' 1 Minnewashta tl Lake 117 4 ■j� 'k 1,1■. Lotus 1 1 Lake \ ,Harrison Lucy if 111,401. Lake A' io t St.Joe II III 1 h Lake r ;$4- Ann W� !i ! a ika \ % dirilit iii_i.i, ,e.g.. ..... ....-di i rill!1111-411 11111111„e Are 11 ' us 110 _vs „0„,, e ilia It 1 18 0411,er Lake isC i ► ` Susan RiceLake Marsh ' : eta' — ! , ,e, V 17 plAir- 11 1 i I .1111111 • Mt' vacs I i 117 Bj4�� , Elt - Riley ,I,„,...j(,,.C, ,, 4. l . Lake @Pi � 1 l -q� 14 ` ___ 1 1 1 1 1 , 1 1 t 1 ' Ricei i Lake; PyS�MPbon Cr 1 Villit r.■■IM■■�■ ■.=■■�■■i ) i 1 eC il. i 1 ,,60 Re J N 1 0.5 0 1 i I Miles Source: Minnesota DNR. Page 12-4 Appendix A Land and Water Resources Inventory The Bluff Creek Turbidity and Fish Biota TMDL and its associated Biological Stressor Identification Study assessed water quality conditions in Bluff Creek to determine the potential cause or causes of impairment of its fish community. Monitoring data from 1991 through 2008 were reviewed. Dissolved oxygen concentrations were adequate to support aquatic life. High nutrient and sediment concentrations and loads in the Creek were mostly associated with storm events, washed off from the watershed. The Creek does not meet state standards for turbidity as measured by Total Suspended Solids (TSS) concentration. The TMDL found that the source of the excess TSS was both watershed load and also sediment contributed from streambank and gully erosion. No water quality data is available for Riley Creek in Chanhassen, or for Assumption Creek. 2.1.4 Wetlands The US Fish and Wildlife Service compiled wetland maps from aerial photo interpretation as part of the National Wetland Inventory (NWI). Wetland scientists use two common classification schemes to identify wetland type—the US Fish and Wildlife Service's "Circular 39" system, and a replacement classification system developed by Cowardin et al. for the Fish and Wildlife Service, commonly referred to as the Cowardin system.The Circular 39 system was originally developed as a means for classifying wetlands for waterfowl habitat purposes. Nine of the Circular 39 freshwater wetland types are found in Minnesota. The Cowardin scheme is a hierarchical classification based on landscape position, substrate, flooding regime, and vegetation. While the Cowardin scheme has been officially adopted by the Fish and Wildlife Service and other agencies,the Circular 39 system is still commonly used because of its simplicity and ease of use. The original NWI was developed in the 1980s from aerial photography.The DNR is updating the NWI statewide using remote sensing imagery; the East-Central region of Minnesota, including Carver County, was reevaluated using 2010 and 2011 imagery. According to the updated NWI (Figure 2.3 and Table 2.5, wetlands, including lakes, cover approximately 27.3 percent of the city's surface.The NWI map is not considered definitive. A delineation of wetland boundaries is required to be completed any time development or other impacts may occur near or in a wetland. Table 2.5. NWI wetland area by type in the City of Chanhassen. Circular 39 Type Acres Percent Cowardin Type Acres Percent 1- Seasonally Flooded 1,077.78 7.4% Emergent(EM) 1,619.9 11.1% 2 Wet Meadow Unconsolidated Bottom 4.05 0.0% (UB) 1,483.8 10.1% 3- Shallow Marsh 906.68 6.2% Forested (FO) 387.6 2.6% 4- Deep Marsh 123.87 0.8% Aquatic Bed (AB) 310.0 2.1% 5- Shallow Open Water 1,638.66 11.2% Upland Scrub-shrub(SS) 198.6 1.4% 6- Shrub Swamp 198.60 1.4% Unconsolidated Shore(US) 2.8 0.0% 7- Wooded Swamp 1.70 0.0% Upland 10,656.6 72.7% 80-Mun.and Indus.Activities 12.36 0.1% Grand Total 14,659.3 90-Riverine 39.02 0.3% 98- Uplands 10,656.58 72.7% Grand Total 14,659.3 Source: Minnesota DNR, 2013 NWI Update East-Central Minnesota. Page 12-1 Appendix A Land and Water Resources Inventory The City has also completed its own wetland inventory and functions and values assessment.A functions and values assessment uses a structured methodology to evaluate the condition of the wetland and its function as part of the overall ecosystem. Examples of the features assessed include vegetative quality and diversity, habitat diversity, flood attenuation, human disturbance, etc. Each wetland is assigned to one of five classifications based on its weighted score: Outstanding, Preserve, Manage 1, Manage 2, or Manage 3. The City's Wetland Protection ordinance (Section 20.401—20.421) regulates requirements for structure setbacks and wetland buffer widths based on each wetland's management classification. The City maintains an Official Map of wetlands by classification that is continuously updated. 2.1.5 Public Waters State Statutes classify certain waterbodies as Waters of the State and the DNR maintains maps and lists on the Public Waters Inventory (PWI). Public Waters wetlands include all type 3, type 4, and type 5 wetlands (as defined in U.S. Fish and Wildlife Service Circular No. 39, 1971) that are 10 acres or more in size in unincorporated areas or 2.5 acres or more in size in incorporated areas. There are 12 public waters basins (lakes) and 21 public waters wetlands in Chanhassen. Public watercourses are defined as natural and altered watercourses with a total drainage area greater than two square miles or natural and altered watercourses designated by the DNR commissioner as trout streams. Public watercourses in Chanhassen include Bluff, Riley, and Assumption Creeks, the outlet of Lotus Lake (Purgatory Creek), and the outlet of Lake Minnewashta that flows to Lake Virginia. Work within waterbodies designated on the PWI is regulated by the DNR. Public waters wetlands and watercourses are shown on Figure 2.4. 2.1.6 Special Waters As noted above, two Outstanding Resource Value Waters are located within Chanhassen: Seminary Fen, a calcareous fen, and Assumption Creek, a trout stream.These are shown on Figure 1.3 above. Page 12-2 Appendix A Land and Water Resources Inventory 1 MI as_ _ 82 ilkChristmas ` e • �!/" FIlii Asi like 'r ` per- WI Idlir /14\ . i-1"11, at • i r . �� )? iti I or, . ;I lane 117 J�/ .y,,i 14r, ..tiarrlionAP- st,„_,,, lit • 1%14 - 4Mlip 1 �• � fs 07 111.11t# Ili 1 lab '- Lk '.6, ' ■sO afe. _ - .), 1111-. '.�. I wow : _ oilohi...4_,Nell.,,iiro)) ME . 19 , c, 1 pis '� lop 00,,, 1 N 0.A 0411111k11 18 i j 4 : iall,zif : , j..,' ,3 in 0(4 L_ _ : _ � el 1 117 ' 6 7 1041 sic Pk N - 1 . ..,, . Ai 1.1 1.4...4. 1r 41° ft : NWI Circular 39 Wetland Classification ! 1 -Seasonally Flooded Basin or Flat ! \ 2-Wet Meadow ` 61! II( lir 3-Shallow Marsh101114101"Cr 4-Deep Marsh 5-Shallow Open Water t , \ '•—••� ..., 6-Shrub Swamp \ ¢ tvil N lilt 7-Wooded Swamp i to,eso° 8-Bogs Municipal and Industrial Activities 1 0.5 0 1 Riverine Systems ��si Miles Figure 2.3. Chanhassen wetlands on the National Wetlands Inventory. Source: Minnesota DNR. Page 12-3 Appendix A Land and Water Resources Inventory i it 1 _ , a _ 82 Christmas/ . i4/4~ �� ... — kisDake •may .....■ .7. „.,,,,, ,I; ,4 ..._•. T. irt ::, 7 lira .- so 9 I' . 7,1111 i V • 1p 1171 r /WARP ` lake (-, �j „„ S , .Hantson mew ■ . ' .. ..,„,:. A To. okr Al ! - a ta 4 -a; , u ______ ilk--Itatty _-___...„..,,c4„ ,Itila Illa Olisso.$°$ 1.114 ' ,.' 1-- ibiluolOP--) ,s 0 /aaa.aaa.fir 4 . ...I It Pis potir ...- :71---, .1, 1 18 1 bop PleitiCill 1 NIM 11 T 1.0-0 er's l'i.7 p 00.,.__ _ : IP II-or- il i 4ti . . m.,,,L64- . r .rte, 117 BC4 'd/ U nisi% 44 • 1•410,„ 14 ,. .1 _ - ! 1 ,,1 , 0 i i k„ 1 .. : - s1 iy,,mp on Cr � % pe 1IP j ram semsai fr.. 11 i e5ot0,C N Public Waters Inventory Basins 1 0.5 0 1 lommeem Public Waters Inventory Streams �ii mom�somim Miles Figure 2.4. Chanhassen lakes and streams on the DNR Public Waters Inventory. Source: Minnesota DNR. Page 12-4 Appendix A Land and Water Resources Inventory 2.1.7 Groundwater Chanhassen relies on groundwater for its municipal water system, operating ten wells drawing water from the Prairie du Chien-Jordan and Prairie du Chien-Wonewoc aquifers. The City manages groundwater principally through its Wellhead Protection Plan (WHPP), which was updated in 2012. This plan provides comprehensive guidance to protect wellhead areas from contamination while meeting the requirements of the Federal Safe Drinking Water Act and the Minnesota Groundwater Protection Act. The purpose of the WHPP is to provide measures needed to protect the groundwater entering and flowing through this area in order to protect our drinking water supply from contamination. The following items are included in the WHPP: • Delineation of the Wellhead Protection Area (WHPA)and Drinking Water Supply Management Area (DWSMA)for the public water supply system • Identification of potential sources of contamination to the DWSMA as well as the degrees of risk of land uses within this area • Definition of goals and objectives and set priorities to manage the Tisk and/or potential contaminant sources to minimize impacts to the DWSMA • Identification of monitoring methods to track the effectiveness of the goals and objectives • Planning contingency measures to address potential interruption of public water supply if contaminants are identified within the DWSMA The Carver County Groundwater Plan was updated in 2016 and contains goals, objectives, and strategies for protecting groundwater resources. It is focused on preventing groundwater contamination, ensuring the continued groundwater supply, and protecting groundwater dependent natural resources like the Seminary Fen and Assumption Creek from the impacts of groundwater withdrawals and groundwater contamination 2.1.8 Floodplain As a part of the FEMA Map Modernization Program, the Federal Flood Insurance Program has delineated the floodplain in Chanhassen and includes floodway and flood fringe areas inundated as a result of the 1-percent annual chance (100-year)flood. The 1-percent annual chance (100-year) floodplain, as defined by the Flood Insurance Program for flood insurance purposes, was detailed by a Flood Insurance Study.The resultant maps are expected to be adopted in 2017 and will be on file at City Hall and with the DNR and are available from the Federal Emergency Management Agency(FEMA). Land use regulations define the floodplain as the area covered by the flood that has a one percent chance of occurring each year, also known as the 100-year flood. The floodplain is divided into two zoning districts: the floodway and flood fringe. The floodway includes the river channel and nearby land areas which must remain open to discharge the 100-year flood. The flood fringe, while in the flood plain, lies outside the floodway. Regulations usually allow development in the flood fringe but require flood-proofing or raising to the legal flood protection elevation. The City has a floodplain overlay district ordinance in effect that establishes allowable uses and in the floodplain, floodway, and flood fringe.That ordinance requires that fill or excavation within the floodplain is subject to a conditional use permit. Page 12-5 Appendix A Land and Water Resources Inventory ,1 ■mm ....Ammo ■ 82 Christmas `L. �� ',� �� .� Lake ■ n=u ■m „. .,i,l.A,....-N...B ..0p a . 1 s .iam,r . . Lake gr ft4 �' 1= Minnewashta if - •Lake 117, LTn 4, v� Lotus Lake .fi■, I■' Lake_, i Lake \ Harrtson Lucy 41411111 + St.Joe i41 Oar LI.1 9 410,1 zIh „,,, drtt$114:-. : ey, N 4,, i _ , iipr....... 18 '. .., ge• .'' i Ngrall �I F' 9111/411111 Lake • n , Susan -' `�R!ce Ma��h : be4 Lake i el ,- • 7.--- 1 00* 17 dip , :1„..- .� 1 a. 117 Bi 14 MEI- Riley '� ,. Lake 01 i mi 4i 4ir 411111” I Floodpin ! Cion Cr 500 Year(0.2-Pct) P^s us. w f LR.ke, 1 r.■■IMI■■_. .■_■.MB.,a j Ill ''+'4' ! VCIe a 1 �ege� < N o 1 0.5 0 1 moss moo imwm Miles Figure 2.5. FEMA floodplain in Chanhassen. Source: DNR Preliminary Map Modernization Data. Page 12-6 Appendix A Land and Water Resources Inventory 3.0 Subwatershed Summaries As part of this Plan,the HydroCAD hydrologic and hydraulic models for the City were updated to include the most recent watershed and basin information and the newly-redefined 100-year Atlas 14 precipitation event. In 2014, the National Weather Service Hydrometeorological Design Studies Center released NOAA Atlas 14,Volume 8, detailing updated precipitation frequency estimates.The new estimates are based on improvements in three primary areas: denser precipitation data networks with a longer period of record, advanced statistical techniques, and new techniques for spatial interpolation and mapping.Atlas 14 improves the accuracy of the precipitation frequency estimates, and supersedes older references, including the commonly-used Technical Paper 40, which was published in 1961. Nine major subwatersheds were modeled (Table 3.1 and Figure 3.1), along with several small areas designed under the classification "Drainage to Other Communities."The purpose of performing this modeling is for planning-level assessments.The models were not calibrated to actual runoff and flows, and are not intended to be flood studies. Model output is quite lengthy and is available electronically.The models and output files are incorporated into this Plan as Appendix B. The following sections briefly describe each of the subwatersheds and their features and issues and opportunities where available. Table 3.1. Chanhassen modeled subwatersheds. Subwatershed Area Area %of Total (acres) (sq mi) Lotus Lake 1,318.0 2.06 9.0 Lake Minnewashta 2,538.4 3.97 17.3 Lake Lucy 949.9 1.48 6.5 Lake Ann 257.2 0.40 1.8 Lake Susan 1,250.9 1.95 8.5 Rice Marsh Lake 718.7 1.12 4.9 Lake Riley 928.0 1.45 6.3 Bluff Creek 4,164.6 6.51 28.4 Lower Minnesota 1,334.9 2.09 9.1 To Neighboring Communities 1,199.2 1.87 8.2 TOTAL 14,659.7 22.91 Page 13-1 Appendix A Land and Water Resources Inventory U j.4........... ...Hi. Christman , is ( zii , Lake C) VI:i 1 Minnewashta Lotus I Lake' 1117 Lake ILake' _ Harrison ( Lake `-`Luc `-St.Joe "— � ).�:4) , / lake \ Anil 1 h% i•'1 coy °4 1'. -, 19 W. .........4 i MEOW 1 La!:e Rice Mai h Susan ' Lake I tit. I 1 Et i Bluff Creek 117 1 Filey _ ' i Lake Lake Ann i-..._! Lake Lucy 1 I Lake Minnewashta "06. , t j 1 Lake Riley ; i m, Lake Susan ! , moo, 1 i °ef - Lotus Lake 1 61 (, • Lower Minnesota 'Rice! i Lake. Rice Marsh .� PS °mpt0n Cr ; •' P rnimam■ um..m..i To Neighboring Communities f i i• ' i taR0Oe' N C s 1 0.5 0 1 ��—� Miles Figure 3.1. Chanhassen modeled subwatersheds. Page 13-2 Appendix A Land and Water Resources Inventory 3.1 LOTUS LAKE SUBWATERSHED 3.1.1 Subwatershed Characteristics The Lotus Lake subwatershed (Figure 3.2) is over 1,000 acres in size, with a majority of the land cover in single-family residential (Table 3.2). There is a substantial (50-90 foot) drop from the highlands on the west side of the lake to the lake. A large ravine originates in LL 1-7 and LL 1-6 and flows through pond LL 1-5 to Lotus Lake. Lotus Lake discharges into and is the headwaters of Purgatory Creek.Another ravine flows from Kerber Pond in LL 5-1 to the lake, and another from LL 6-2 to the lake. Numerous ponds and wetlands dot the subwatershed. irmigiy---", ir 11011 OF 41 lillkii 4 1-13 1.19111 ellllif 111Illeirre 4111110111111111) 4-1 1-23 1- III1-2 C. vei Be ch 1-0 1.1.5 1-1 . 1-10 1-4 1-21 1-20mot '.. 8-3 1-7 sarin!,, 142 0 1- 8-2 5-1 1-6 lAlli* a 00o 5-2 °�' z&2 IN1-18 0 ' Santa f e 1 o 1-25 Subwatersheds ` 7-1 WE —40 Direction of Flow s 0 0.125 0.25 0.5 0.75 1 Miles Figure 3.2.The Lotus Lake subwatershed. Page 13-3 Appendix A Land and Water Resources Inventory Table 3.2. Lotus Lake subwatershed 2010 land use. Land Use Area(ac) Percent Residential Low Density 734.2 69% Right Of Way 157.1 15% Parks Open Space 101.6 10% Public Semi Public 50.4 5% Residential Medium Density 20.7 2% Residential High Density 4.1 <1% 1,068.1 100% 3.1.2 Issues &Opportunities Lotus Lake Water Quality. Lotus Lake is classified as a deep lake, with a surface area of 246 acres and a maximum depth of nearly 30 feet. Water quality in the lake does not meet State of Minnesota standards, with excessive nutrient and chlorophyll-a concentrations and poor water clarity. In 2015, the DNR conducted a survey of the quality and ecologic integrity of the fish community in the lake using a tool called the Fish Index of Biotic Integrity (F-IBI).That analysis indicated that the fish community is impaired compared to similar lakes, with some pollution-tolerant species and no pollution-intolerant species present, a lack of vegetation-dwelling fish and a low biomass of top carnivores. Common carp are present in the lake, and efforts to reduce the population and biomass appear at this time to be successful. An aquatic vegetation survey found mostly native vegetation with the invasive Eurasian watermilfoil and curly-leaf pondweed at low abundance. A Use Attainability Analysis(UAA), which is a diagnostic study similar to a Total Maximum Daily Load (TMDL) study, was completed in 2016 (Barr 2016).This analysis estimated that just under 30 percent of the nutrient load to the lake came from watershed sources. Ponds and wetlands in the Lotus Lake subwatershed provide filtering and settling of the particulate matter in stormwater, removing a significant amount of total phosphorus (TP). However,these types of practices do little to remove dissolved phosphorus. Over two-thirds of the load to the lake comes from internal sources, mostly release from the sediments during extended periods of low-oxygen conditions at the lakebed.To improve water quality to meet state water quality standards and enhance conditions for fish, phosphorus from watershed and internal sources needs to be reduced by 37 percent from the existing condition. The UAA identified several potential Best Management Practices (BMPs) that could be considered in this subwatershed. Treatment practices that can remove dissolved TP such as infiltration and enhanced filtration practices in addition to practices in currently untreated areas could help reduce nutrients conveyed from the watershed. An internal load project such as an alum treatment could significantly reduce internal load form sediment release. Ravine Stabilization. A project to stabilize 1,540 lineal feet of deeply incised channel between Carver Beach Road and Lotus Lake is included in the CIP and Implementation Plan in 2018. Page 13-4 Appendix A Land and Water Resources Inventory 3.2 LAKE MINNEWASHTA SUBWATERSHED 3.2.1 Subwatershed Characteristics The Lake Minnewashta subwatershed (Figure 3.3) is the second largest in the city, and is dominated by the 738 acre Lake Minnewashta (Table 3.3). Parks and Open Space are also a defining feature, as the subwatershed includes Lake Minnewashta Regional Park Large, portions of the University of Minnesota Landscape Arboretum and Horticultural Research Center, and Camp Fire MN's Camp Tanadoona.There are a number of mostly small, direct drainage subwatersheds. Lake St.Joe, a small but deep lake surrounded by wetlands, discharges through storm sewer to Lake Minnewashta. Lake Minnewashta outlets through a channel to Lake Virginia in the city of Victoria and ultimately to Lake Minnetonka. Table 3.3. Lake Minnewashta subwatershed 2010 land use. Land Use Area(ac) Percent Public Semi Public 716.4 40% Residential Low Density 523.6 29% Parks Open Space 370.9 21% Right Of Way 137.1 8% Residential Large Lot 27.1 2% Residential Medium Density 8.7 <1% Commercial 7.5 <1% Office 2.2 <1% 1,793.5 100% 3.2.2 Issues &Opportunities Lake Water Quality. Both Lake Minnewashta and Lake St.Joe are deep lakes with good water quality. The City will continue to undertake BMP5 as opportunities arise and will work with residents and other stakeholders to undertake improvements to help preserve this water quality. Aquatic Invasive Species. Lake Minnewashta has been infested with Eurasian watermilfoil, curlyleaf pondweed and zebra mussels.There are partnership opportunities with the Minnehaha Creek Watershed District and the Lake Minnewashta Preservation Association continue to monitor any impacts or trends related to the zebra mussel infestation and other invasive species. Page 13-5 Appendix A Land and Water Resources Inventory 4freitp Ix; " 41'11 1111‘ . "It,„„iii, 1,00 t T•,� � .0 5•b iii, lika ki 11,,,, it,e. .....4„4/01ar Otsvir r i flatkailli or Ai, A 2.10 ilre 41111100r10 Subwatersheds It+E --► Direction of Flow 0 0.25 0.5 1 Miles Figure 3.3. Lake Minnewashta subwatershed. Page I 3-6 Appendix A Land and Water Resources Inventory 3.3 LAKE LUCY SUBWATERSHED 3.3.1 Subwatershed Characteristics The Lake Lucy subwatershed (Figure 3.4) is located in the north-central part of the city. Land use in the subwatershed (Table 3.4) consists almost entirely of single family residential parcels and associated road right of way. Some large-lot residential is present. Pheasant Hills Park is the largest park in the subwatershed. Runoff from the upper subwatershed is collected in a series of ponds and flows through storm sewer along Lake Lucy Road to Lake Lucy.The upper watershed has two main collection systems, south along Galpin and east along Lake Lucy Road, the other flows from 63rd street to the wetland system south of Lake Lucy Lane. Wetlands and open space dominate the lower subwatershed. Lake Lucy outlets into Lake Ann by a short channel. Tior 4-5 4 ‘tri 16:1 4-8 4-9 2-14 8-bY :44 -1 5.2 4111L4Filliref"9-itliat411.1111tril 5-! 1 Atilf S-4 =8 401)% 1-2 162-6 Subwatersheds 2-19 E 4 -� Direction of Flow 0 0.25 0.5 1 Miles Figure 3.4. Lake Lucy subwatershed. Page 13-7 Appendix A Land and Water Resources Inventory Table 3.4. Lake Lucy subwatershed 2010 land use. Land Use Area(ac) Percent Residential Low Density 625.9 73% Right Of Way 88.2 10% Residential Large Lot 74.2 9% Parks Open Space 60.5 7% Public Semi Public 6.8 1% Residential Medium Density 2.6 <1% 858.2 100% 3.3.2 Issues &Opportunities Potential Street Flooding. Modeling suggested a possibility of pond P-LU 3-4 overtopping Manchester Drive during a 100-year event. However, during the June 2014 wet period no flooding was observed. This location will continue to be monitored during large rain events. Lake Water Quality. Lake Lucy is considered to be a shallow lake and its water quality hovers near the state's shallow lake standards for nutrient concentration. Section 3.3.2 of the Plan describes the findings of a UAA for Lake Lucy and Lake Ann. Several potential actions were identified to improve water quality in Lake Lucy, including potential phosphorus load reductions in the watershed, a potential alum treatment to reduce nutrient loading from the sediments, and management of invasive aquatic vegetation in the lake. The City will continue to work with the RPBCWD to partner on potential improvement projects and will continue to undertake BMPs as opportunities arise. Page 13-8 Appendix A Land and Water Resources Inventory 3.4 LAKE ANN SUBWATERSHED 3.4.1 Subwatershed Characteristics The Lake Ann direct subwatershed (Figure 3.5) is a small drainage area that flows overland directly to the lake. Lake Lucy flows into Lake Ann through a small channel on the north side of the lake. Land use is primarily parks and open space and public/semi-public uses (Table 3.5). The Temple of Eck owns a substantial amount of open space.The outlet of Lake Ann is the headwaters of Riley Creek. IILI:il Irstilitt 1-10 IP' 1-9 111 Subwatershedsi ll ----► Direction of Flow " PE r ' 0 0.125 0.25 0.5 Milesilk Figure 3.5. Lake Ann subwatershed. Table 3.5. Lake Ann subwatershed 2010 land use. Land Use Area(ac) Percent Public Semi Public 40.5 30% Residential Low Density 38.0 28% Parks Open Space 36.2 27% Residential Medium Density 17.8 13% Residential High Density 1.1 1% Right Of Way 0.9 1% 134.6 100% Page 13-9 Appendix A Land and Water Resources Inventory 3.4.2 Issues &Opportunities Lake Water Quality. The water quality in Lake Ann currently is better than the state's standard. However, the lake does experience occasional blue-green algal blooms, Section 3.3.2 of the Plan describes the findings of a UAA for Lake Lucy and Lake Ann. As the water quality in outflow from Lake Lucy can affect water quality in Lake Ann, improvements to Lake Lucy will help to protect Lake Ann. The City will continue to work with the RPBCWD to partner on potential improvement projects and will continue to undertake BMPs as opportunities arise. Page 13-10 Appendix A Land and Water Resources Inventory 3.5 LAKE SUSAN SUBWATERSHED 3.5.1 Subwatershed Characteristics The Lake Susan subwatershed includes part of the City's commercial/industrial core (Table 3.6) as well as parks and open space. There are five major subdrainage systems in the subwatershed (Figure 3.6). Riley Creek drains the upper subwatershed. The area west of Karber Boulevard and north of Santa Vera Drive flows through wetlands and channels southeast to Riley Creek. Drainage from the area south of Highway 5 is collected in storm sewer and ponds which are routed into Riley Creek.The southern part of the subwatershed flows into a large wetland complex in the Lake Susan Preserve (LS 2-3), which flows to Lake Susan. Commercial and industrial land uses in the vicinity of Highway 5 and Highway 101 are routed to a large pond (LS 3-1) west of Lake Susan Park. Residential development around the lake flows overland to the lake. Lake Susan outlets into Riley Creek, which then flows to Rice Marsh Lake. Table 3.6. Lake Susan subwatershed 2010 land use. Land Use Area(ac) Percent Office Industrial 270.0 21% Right Of Way 219.5 17% Parks Open Space 197.2 15% Residential Low Density 196.6 15% Commercial 138.3 11% Public Semi Public 82.0 6% Residential High Density 62.7 5% Office 38.1 3% Residential Medium Density 37.7 3% Agriculture 26.6 2% Residential Large Lot 20.7 2% Mixed 6.2 <1% 1,295.5 100% 3.5.2 Issues & Opportunities Lake Water'-Quality. Lake Susan is a shallow lake that has poor water quality. Water clarity has improved in the past several years, possibly in response to the reduction of a large population of carp to more manageable levels, and to treatment of the invasive curly-leaf pondweed.A Use Attainability Assessment completed in 2013 reviewed potential options for improving water quality. In 2016 the RPBCWD and City partnered to contract a spent lime treatment system to treat discharge from the wetland complex in the Lake Susan Preserve. The RPBCWD is currently evaluating the feasibility of a whole-lake alum treatment for Susan as well as other BMPs identified in the UAA. A partnership project with RPBCWD to install pump and treatment device to withdraw water from Lake Susan Pond to irrigate Lake Susan Park is included in the CIP and Implementation Plan in 2017.The City will continue to work with the RPBCWD to partner on potential improvement projects and will continue to undertake BMPs as opportunities arise. A project to stabilize a segment of Riley Creek adjacent to the City's Public Works Faciality is in the CIP and Implementation Plan in 2019.This project will reduce sediment and nutrient load in the creek and conveyed to Lake Susan. Page 13-11 Appendix A Land and Water Resources Inventory 7 1 5-10 5-4 1(5-5 , 5-20 5-14 , 111‘11.441411** 5-18 eirowir 5-17 5-16 fiAll 5-19 r • 5-8 3-6 4-9 0. 104t. _.f 4-8 4-6 10. 411130. -10 Direction of Flow 2-4 Subwatersheds ifiir 2-3 2-6 2-13 1 r SIVA 2-11 0 44 2-9 2-10 x1 2-12 ll'-+F S Ark 0 0.25 0.5 1 iissillimilli Miles Figure 3.6. Lake Susan subwatershed. Page 1342 Appendix A Land and Water Resources Inventory 3.6 RICE MARSH LAKE SUBWATERSHED 3.6.1 Subwatershed Characteristics Rice Marsh Lake straddles the boundary of Chanhassen and Eden Prairie, and its lakeshed encompasses land in both cities. Within Chanhassen the Rice Marsh Lake subwatershed (Figure 3.7) has two distinct land uses. North of Highway 5 and at the southeast quadrant of Highway 5 and Great Plains Boulevard is highly impervious commercial property(Table 3.7). Single-family and medium density residential lies between Highway 5 and Highway 212. Wide riparian wetlands and wooded areas surround Rice Marsh Lake Park, which extends into Eden Prairie. Lake Susan to the west outlets into Rice Marsh Lake via Riley Creek. Rice Marsh outlets via Riley Creek in Eden Prairie,where it flows into Lake Riley. A winter aeration system is operated on the lake to support the bluegill population that keep invasive carp in check. Table 3.7. Rice Marsh Lake subwatershed 2010 land use. Land Use Area(ac) Percent Residential Low Density 190.8 27% Right Of Way 139.4 19% Parks Open Space 101.2 14% Commercial 96.3 13% Mixed 58.8 8% Residential Medium Density 51.7 7% Public Semi Public 38.2 5% Residential High Density 20.1 3% Office Industrial 18.5 3% 715.0 , 100% 3.6.2 Issues&Opportunities Potential Flooding. Modeling identifies potential flooding issues in RM 3-3. Private ponds have the potential to overflow onto private property. Lake Water Quality. Water quality and clarity has improved in Rich Marsh Lake since the 1970s, when wastewater treatment plant effluent was discharged into the lake. However, it is still classified as an Impaired Water and does not meet nutrient standards for a shallow lake. At an average depth of only five feet, sediment cores suggest that it has always been a eutrophic lake A UAA was completed in 2016 to evaluate conditions and identify options for improvement. Modeling suggests that excess nutrients in Rice Marsh Lake are contributed from the watershed, from outflow of Lake Susan conveyed by Riley Creek, and from internal sediment release. Recommended strategies include increasing water quality treatment in the watershed, improving water quality in Lake Susan, and applying alum to the lake to seal sediments and reduce phosphorus release. A partnership project with RPBCWD to install an iron-enhanced sand filter within Rice Marsh Park is included in the CIP and Implementation Plan in 2019. The City will continue to work with the RPBCWD to partner on potential improvement projects and will continue to undertake BMPs as opportunities arise. Page 13-13 Appendix A Land and Water Resources Inventory a: > > a a z 3 p . .----..---.'\ 3-6 a z " Y i n 5-1 5-2 Chanhassen 5-3 W 7E 4: • •'i0' �� 1-6 • 3-'3 a) ji 3-1 ti � • : L Q R 1-12 1 i I 0.11 . (se 4) V� \} C c S 1-9 lip 12-6 44ers41-11 1-10 tillitol 1-2 1-1 lir1-4 481411 1-8 —i Direction of Flow N � Subwatersheds w.+E 0 0.125 0.25 0.5 lismm Miles Figure 3.7. Rice Marsh Lake subwatershed. Page 13-14 Appendix A Land and Water Resources Inventory 3.7 LAKE RILEY SUBWATERSHED 3.7.1 Subwatershed Characteristics Lake Riley straddles the Chanhassen/Eden Prairie border and its lakeshed encompasses land in both cities. Rice Marsh Lake to the north outlets into Lake Riley through Riley Creek in Eden Prairie. Within Chanhassen the Lake Riley subwatershed (Figure 3.8) is comprised of mainly large-lot and low density residential uses (Table 3.8), with a significant amount of Highway 212 right of way. The outlet of Lake Riley, which is in the city of Eden Prairie, is Riley Creek, which flows down the Minnesota River bluff to Grass Lake and then to the river. Table 3.8. Lake Riley subwatershed 2010 land use. Land Use Area(ac) Percent Residential Low Density 363.5 44% Residential Large Lot 189.7 23% Right Of Way 141.2 17% Residential High Density 49.6 6% Mixed 41.8 5% Parks Open Space 41.7 5% Residential Medium Density 0.2 0% 827.6 100% 3.7.2 Issues & Opportunities Potential Flooding. Modeling identifies potential flooding issues. Modeling predicts an overtopping possibility for a pond in LR 3-2 at Lake Riley Boulevard and Lyman Boulevard.This is a location that is known to experience street flooding during large rain events. Street flooding was observed during the October 2014 25-year rain event. City staff regularly check this location during rain events. Modeling also predicts that a wetland just to the north of Lyman Boulevard could possibly overtop.This location is checked periodically by City staff as well. Lake Water Quality. Water quality in Lake Riley hovers around the deep lake standards for recreation in Minnesota. A UAA was completed in 2016 to evaluate conditions and identify options for improvement. Recommended strategies include increasing water quality treatment in the watershed, improving water quality in upstream Lake Susan and Rice Marsh Lake, and applying alum to the lake to seal sediments and reduce phosphorus release. The RPBCWD applied an alum treatment to Lake Riley in 2016, which brought an immediate improvement in lake water quality and clarity as well as an improvement in native aquatic vegetation abundance.The lake has also been treated for invasive curly-leaf pondweed and Eurasian watermilfoil and will continue to be spot treated as necessary. The City will continue to work with the RPBCWD to partner on potential improvement projects and will continue to undertake BMPs as opportunities arise. Page 13-15 Appendix A Land and Water Resources Inventory 2-3 r 2-5 J3-8 2-47 3-9 2-6 -1 3-10 AllinfrianjW0 el 1-1 A -!, 1-5 1-8 1-7 Ili V4 1-9 1 4-5 4-1* 4-4 r IA, rb ,,'+-E -► Direction of Flow Ilik 0 0.125 0.25 0.5 Subwatersheds limimm Miles Figure 3.8. Lake Riley subwatershed. Page 13-16 Appendix A Land and Water Resources Inventory 3.8 BLUFF CREEK SUBWATERSHED 3.8.1 Subwatershed Characteristics The Bluff Creek subwatershed is the largest in Chanhassen, draining almost 4,200 acres.The Creek rises in a large wetland complex in subwatershed BC 2-1. In general, stormwater from the central core of the city is collected in a series of storm sewers and ponds which are discharged in the Creek. The lower subwatershed is less developed than the upper subwatershed. Below Highway 212, runoff is conveyed down the bluff through a series of ravines. Table 3.9. Bluff Creek subwatershed 2010 land use. Land Use Area(ac) Percent Residential Low Density 1,370.3 33% Right Of Way 632.7 15% Parks Open Space 446.7 11% Office Industrial 427.5 10% Residential Large Lot 319.0 8% Residential Medium Density 274.0 7% Agriculture 213.7 5% Public Semi Public 169.0 4% Office 145.6 3% Residential High Density 94.9 2% Commercial 86.0 2% Mixed 9.0 <1% Total 4,188.5 100% 3.8.2 Issues&Opportunities Water Quality and Biotic Integrity TMDL. As discussed in Section 2.1.3 of this Plan, a turbidity and fish biota TMDL was completed in 2013 to diagnose pollutant sources and biotic stressors and identify implementation actions. The TMDL found that the source of excess TSS was both watershed load and also sediment contributed from streambank and gully erosion, especially downstream of Pioneer Trail, during high flow events. Excess turbidity from TSS load was also identified as one of the primary stressors to the fish community. A stream and gully assessment downstream of Pioneer Trail evaluated conditions rated the severity of erosion. In 2014 the City completed the stabilization of Ravine 2. Habitat fragmentation was also identified as a stressor, singling out the large drop at the regional trail crossing culvert.A project to stabilize the stream at this location and create a fish passage was proposed for 2017, but the City and RPBCWD were unable to secure a required easement form the landowner. An additional project is included in the City's CIP and Implementation plan for 2019 to add volume reduction and rate control BMPs in the subwatershed. Stream Condition. In 2017 the RPBCWD developed its Creek Restoration Action Strategy(CRAS)to help guide future actions to protect and improve Bluff Creek as well as other major streams in that watershed. The CRAS combines stream physical condition and stability, water quality, and other attributes into a classification and prioritization system. Four segments on Bluff Creek and one on a tributary were rated as "severe," with poor water quality, unstable banks experiencing erosion and mass wasting, and limited habitat. Page 13-17 Appendix A Land and Water Resources Inventory IA 6 ,0410 -Er i 41`lt t-.4 _.. , Au mo 13 2-9 : r A, 5-10 1h, t ,wie 4,,,,,fifioe Ilik 5-6 firi1/20(11 I i r Mill Ar tilr1r4 f 68 TW-IS.• 6.9 7-6 610110 If-6-_7 iiiiia - r7-10 ittgr I, 8-6 8-7 i 410 8-10 rit *fild rr 9,174.-1 Illeis � �� yin 8-0 � 8.1' 9-6�- Viiiii9-1 9-1 r 9 � .7 iiii-1 9-16 11 r 9-15 9-25 /i 9-24 10 , i Illi 111 N OP nF 9-1 'Ftii 5 --. Direction of Flow 0.11225 0.5 0.75 1 Illik Subwatersheds — — Miles , Page 13-18 Appendix A Land and Water Resources Inventory 3.9 LOWER MINNESOTA SUBWATERSHED 3.9.1 Subwatershed Characteristics The Lower Minnesota subwatershed (Figure 3.10) is low-density, with grasslands, wetlands, some agriculture, and large-lot residential development (Table 3.10).This subwatershed includes Assumption Creek, a designated trout stream, and Seminary Fen and the Seminary Fen Scientific and Natural Area. 4-2 1111111410110, llirlirriath 0111141411111 .1 2-! • Seminary Fen SNA ,ek r • 2-4 1-1 et • sota R‘ • Fens rIims Subwatersheds i Regional Parks n l� S Scientific and Natural Areas Direction of Flow 00.126.25 0.5 0.75 1 Miles Figure 3.10. Lower Minnesota River subwatershed. Page 13-19 Appendix A Land and Water Resources Inventory Table 3.10. Lower Minnesota River subwatershed 2010 land use. Land Use Area (ac) Percent Agriculture 655.0 51% Residential Large Lot 340.4 27% Office 153.5 12% Right Of Way 88.6 7% Office Industrial 38.0 3% Residential Low Density 5.9 0% Total 1,281.5 100% 3.9.2 Issues&Opportunities Seminary Fen. The City participates in the Seminary Fen Work Group.with Chaska and the Met Council, which meets periodically to discuss the impacts of groundwater pumping on this rare, protected resource. Page 13-20 Appendix A Land and Water Resources Inventory 3.10 DRAINAGE TO NEIGHBORING COMMUNITIES 3.10.1 Subwatershed Characteristics There are a number of small subwatersheds that flow to receiving waters in adjacent cities. Within the Minnehaha Creek Watershed District, portions of Chanhassen discharge to Lake Virginia, Lake Galpin, and Christmas Lake. Land use in those subwatersheds is almost entirely single-family residential, wetland, or park. Within the RPBCWD, portions of residential areas in Chanhassen are tributary to Silver Lake or Purgatory Creek.The commercial/industrial district at Highway 5 west of Dell Road is tributary to Mitchell Lake in Eden Prairie. Some areas within the Landscape Arboretum and a mixed-use area in the vicinity of Galpin and Lyman Boulevards drain to Lake Hazeltine in the Carver WMO. To To To To Silver La Galpi Christmas , Lake Vi •inia , L,.nr i To •' washta t ht,.. il Fe 41.o,,t .0, Purgatory Creek iii i, 1 Arboretum Ulvd C11:1101.,,.c+, v!Id C21 ''oulter Blvd — To re,i. F; Mitchell 0 To .s,,::$Ct,_ carte ` Lake Lake o `� a ,o sd:a� ,Q Hazeltine CO (f --VOCrAWIr e Ltz Cit. 1 i I 'f I I I OF c�d,,d Or — '-p relirillil ,t nu 4104 X-_,..‘..j - Subwatersheds 0 0.5 1 2 3 4 '+` Miles Figure 3.11. Drainage to neighboring communities. Page I 3-21 Appendix A Land and Water Resources Inventory 3.10.2 Issues & Opportunities Lake Virginia Tributary Area. The outlet of Lake Minnewashta, a channel to Lake Virginia,flows under several driveways that are undersized for large events. No information is available regarding potential flooding or other issues that may arise. Purgatory Creek Tributary Area. A ravine north of Fox Hollow Drive, west of Fox Drive in PC 2-2 that discharges into the pond at Fox Hollow Drive and Highway 101 needs stabilization. Christmas Lake. The headwaters of Christmas Creek are in Curry Farms Park.The park did experience some flooding in June 2014. Christmas Creek downstream of Powers Boulevard is in need of stabilization. Page 13-22 Appendix A Land and Water Resources Inventory 4.0 References Barr. 2010. Bluff Creek TMDL Biological Stressor Identification. pca.state.mn.us/index.php/view- document.html?gid=13751. Barr. 2013a. Bluff Creek Watershed Total Maximum Daily Load Report:Turbidity and Fish Bioassessment Impairments. pca.state.mn.us/index.php/view-document.html?gid=19684. Barr. 2013b. Lake Lucy and Lake Ann Use Attainability Analysis Update. rpbcwd.org/files/7213/8426/4821/LakeLucv LakeAnn UAAUpdate September2013 FINAL.pdf. Bass. 2013c. Lake Susan Use Attainability Analysis Update. rpbcwd.org/index.php/download file/128/209/ Barr. 2016. Rice Marsh Lake and Lake Riley: Use Attainability Analysis Update. rpbcwd.org/index.php/download file/714/209/ Barr. 2017. Creek Restoration Action Strategy(CRAS) 2017 Report. rpbcwd.org/index.php/download file/1020/197/. Barr. 2017. Lotus,Silver, Duck, Round, Mitchell, Red Rock Use Attainability Analysis Update; Lake Idlewild and Staring Lake Use Attainability Analysis; and Lower Purgatory Creek Stabilization Study. rpbcwd.org/index.php/download file/952/200/ Lusardi, B. 2009. Plate 3 -Surficial Geology. Minnesota Geological Survey, County Atlas Series,Atlas C- 21, Part A. Minnesota DNR. 2017. Lake Finder. dnr.state.mn.us/Iakefind/index.html Minnesota DNR. 2017. Minnesota Biological Survey Native Plant Community and Rare Species County Maps. dnr.state.mn.us/eco/mcbs/maps.html Minnesota Geospatial Commons. 2017.gisdata.mn.gov/ Minnesota Pollution Control Agency. 2017. Environmental Data Application. pca.state.mn.us/data/surface-water-and-stormwater-data Mossler, and V.W. Chandler. 2009. Plate 2 - Bedrock Geology. Minnesota Geological Survey, County Atlas Series, Atlas C-21, Part A. dnr.state.mn.us/waters/programs/gw section/mapping/platesum/carvcga.html NOAA National Climatic Data Center. 2014. 1981-2010 Normals Data Access. www.ncdc.noaa.gov/land- based-station-data/climate-normals/1981-2010-normals-data Ramstack Hobbs,J.M. and M.B. Edlund. 2014. Historical water quality and ecological change in Rice Marsh Lake. Final report submitted to Riley Purgatory Bluff Creek Watershed District. St. Croix Watershed Research Station, Science Museum of Minnesota, Marine on St. Croix, Minnesota, 55047. rpbcwd.org/index.php/download file/418/209/ USDA NRCS. 2016. Soil Survey Geographic (SSURGO) Data Base.www.lib.ncsu.edu/gis/nrcs.html Page 14-1 Appendix A Land and Water Resources Inventory Public Input Themes Summary of Public Input for the City of Chanhassen's Surface Water Management Plan Prepared by ‹...c_____F__ ESHWATER SOCIETY 2424 Territorial Road Suite B I Saint Paul, MN 55114 I freshwater.org In spring 2017, community members representing multiple lakes and areas of the city of Chanhassen gathered to share their thoughts regarding priorities for the city's Surface Water Management Plan update. Recognizing that the city is tasked with managing stormwater, questions did not ask if stormwater practices were desired, but what kind of practices would be most preferred. Emphasis was placed on the need to involve everyone in the work of protecting water,and the benefit of managing stormwater where it falls(when possible). As such,four questions were developed to uncover the types of green infrastructure co-benefits would be desired by residents,as well as gain insight into the issues and opportunities community members see. Questions were answered through small group conversations,and notes taken by conversation participants have been summarized by question in this document. It should be noted that Freshwater Society recognizes that some of the comments and themes are either very lofty or entirely beyond the scope of the Surface Water Management Plan. However,all themes are included without analysis as to feasibility or usefulness so as to provide the most accurate representation of the community input collected. The questions and summaries of the responses are contained on the following pages. Here's what's inside: Page 1 Introduction Page 2 Community Values Page 3 Community Concerns Page 4 Visions of Success Page 5 Strategies to Get There 1 COMMUNITY VALUES Question 1:Thinking about your community or neighborhood,what are the things you value most? Residents value a lot about living in Chanhassen,from environmental qualities to shopping and entertainment. City staff should find opportunities to build in co-benefits to green infrastructure that build on these values. HeoutyF The aesthetics of the community are important--from the beauty of the shoreline to clean and litter-free streets, beauty is of high value. Access to amenities Residents value having access to community amenities.This includes the downtown entertainment and shopping district,the School District,community developments,and area lakes and beaches. Residents value the free and easy access they have to their natural resources and the ability to recreate on land or water. Parks and trails,water access for fishing,swimming, and boating, recreation areas-- these are all a part of what makes Chanhassen great. Quality city services Consistency and reliability of city services is important,whether it is being able to count on responsive staff and public safety officials or being able to count on having adequate flood protection.While residents noted they value Chanhassen's city services,they also mentioned that there are opportunities for improvement, including areas where services like street sweeping and AIS control can help to improve water quality. Natural qualities Residents value clean air, being able to have clean water--for habitat, recreation,and value of clean water in and of itself--and value the many natural qualities of Chanhassen including the trees,the water,the habitat and wildlife,and the peaceful nature of the setting. Characteristics of the community Neighborliness rose to the top as a major value,where people appreciate the safety, sense of community, the friendly interactions they have with each other,and the ability to be actively engaged in building community and/or addressing issues while remaining open to change. Events that celebrate and foster this community are also valued, such as the July 4th Boat Parade and other events where socializing can happen.At the same time, residents also value the peacefulness of the community, and the quiet of lake views. valet Though included under a question asking to understand values, several suggestions were given which indicate that there is a perception of lack of control of vegetation--in and out of water.Additionally,there are requests for increased enforcement of nuisance issues, like weeds and illegal parking. 2 Question 2:Thinking about your community or neighborhood,what concerns do you have? Similarly,there are a number of things that residents find to be cause for concern. When possible,staff should consider building in co-benefits that can seek to address these concerns. Aquatic Invasive Species AIS, including existing infestations as well as those that could come, is of great concern to the community. Continuing with inspections and identifying other ways to control for AIS is strongly desired. Biodiversity There is a perception of lack of biodiversity. Increasing diverse plants along the shoreline and in the lake can provide for water quality and habitat benefits. Community engagement The community needs to be more involved in the work of protecting water,for now as well as the future. This requires two things: increased opportunity for the community to be involved, as well as increased education about what can be done, why, and how. Achievitni bebtiviol CIrt7no There are a number of actions that can be taken to address human impacts on water quality,falling along a spectrum from education to enforcement. Part of this work will be new efforts to set community expectations about what is possible (regarding water quality in general as well as what can be done on and in water--and associated timelines), and part of this will be finding ways to enforce existing rules such as those restricting wakes or promoting boating safety. Project planning and implementation Changes from the city around maintaining existing infrastructure and BMPs are needed, as well as the dedication of more funding to the protection of water resources. Existing funding should be prioritized to address runoff and build projects that will help to clean surface water. New funding sources should be sought to help allocate more funding across otherwise competing priorities. Quality of life Any projects installed should also help to improve overall quality of life,emphasizing what the residents value about the community, such as health and safety. Water quality and level Dead fish,bacteria, harmful (and non-harmful)algal blooms,shoreline erosion,fluctuating water levels, and overabundance of weeds have been observed in recent years.As such, runoff is a major concern-- both runoff from the properties immediately surrounding surface water bodies,as well as the runoff collected and conveyed by stormwater systems.On nearby properties, lack of shoreline habitat or gardens, use of fertilizers,geese,and erosion are the more significant issues.With the stormwater outfalls,the community is concerned that the water just dumps directly into the water bodies--finding ways to mitigate(and if possible,treat)this runoff is strongly desired. 3 C Question 3:In 5 years,what does success look like? Any process of change takes time,and managed expectations as to what is possible is needed. Recognizing that not everything can be done in five years, residents identified the following as intermediate goals. �laltmii( ilrvt).ivk'Spec There are no aquatic invasive species,water clarity has improved with vegetated shorelines, native vegetation,and there is a functioning and healthy fishery. Mainstreamed city processes City maintenance needs will be met on a continuing basis, including dredging of ponds,regular street sweeping, and reduced use of chemicals and fertilizers. Additionally,city processes will function well, and smart changes will be implemented. Community-wide effort All citizens are aware of water quality issues,and understand their part in protecting them. It is important to inform and engage all citizens, not just those that reside on or nearby lakes. Improved health of water bodies There is significant progress toward improving health of local water bodies, and a plan for measuring and continuing to make progress is in place. Lakes are healthy and clean to support fishing and swimming, with reduced algae, less polluted runoff, less erosion and eroded shorelines, no aquatic invasive species, and meeting aquatic standards. Wetlands are protected, and a fully functioning stormwater system is in place. Recreation Lakes are clean and safe to recreate in (perceptually and actually),with access for all citizens to use and enjoy. 4 { Question 4:What strategies would you use to manage water in Chanhassen? After identifying what success looks like in five years, residents were then asked to propose strategies which could help the community arrive at that success. This by far led to the most robust conversation and comments, and produced the most tangible and measurable suggestions. Aquatic invasive species Preventing and managing AIS is a major concern,and needs to be planned for. Specifically, plans are needed for the following: control of carp,continuation of inspections, rapid response for new infestations, and treatment of milfoil. Achieving behavior change The community needs to be able to do their part to care for the water. Many individual actions are available, but education and incentives are needed to see increased adoption of BMPs by those on the lakes as well as anywhere in the lakesheds. Education that is done needs to be more than just the passive provision of information.A marketing strategy should be developed to make doing something about runoff a more attractive option.Things like field trips,watershed tours,community events,and awards for community stewards should be considered. Efforts should also be made to get city staff and officials involved,such as helping council members understand the roles they play or passing policies that restrict observed practices such as washing cement or paint tools into the stormsewers. Regarding policies in general, stiffer penalties may be needed (especially concerning transport of AIS)and,where useful, new regulations or guidelines could be considered to help further encourage behavior change. Project development,management, and implementation New sources of funding should be sought and a plan to prioritize and effectively spend funds should be developed. Funding can be dedicated to specific projects, leveraged with partner sources, or even allocated to residents via cost share. Perhaps one of the most desired changes is implementation of more frequent street sweeping,even up to once per week. Recognizing that not everything will be collected by street sweeping,there is also a desire to maintain and improve existing BMPs while identifying new opportunities to soak more water into the ground and treat stormwater before it reaches surface water bodies. Choosing projects to undertake should be done following a cost-benefit analysis, looking for those projects that will give the biggest "bang for the buck".That said,funding allocation should still follow a balanced approach that takes into account the needs of lakes, creeks, ponds, and even infrastructure. Understanding what is needed, communicating those needs to residents and staff, and identifying how Chanhassen is doing in comparison to neighbors is a good place to start. l E t feats n Where possible, balance recreation opportunity with the need to protect lakes from spread of AIS, and work to ensure they are managed adequately for fishing. Water quality and quantity Control and treat runoff to improve the quality of water entering surface water bodies while reducing the volume to reduce bounce and stream channel erosion.Work with homeowners to help them understand the options available to them to play a role,and provide cost share or other incentives to encourage adoption of BMPs. Likewise,the city should take advantage of opportunities on public lands to increase permeability,allowing more water to soak into the ground where it falls throughout the watershed. 5