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HomeMy WebLinkAboutCH3-NaturalResourcesPLAN OF STILLWATER Chapter 3 : Natural Resources 3-1 Chapter 3 - Natural Resources Introduction Stillwater’s natural resources are among the defining features of the city. Balancing preservation of these features with remaining future growth is an important element of this plan and has been articulated as a priority by city officials and residents. The city’s location along the scenic St. Croix River corridor makes it a desirable environment in which to live, and this contributes to strong growth pressures in the region. Therefore, effective planning that considers the natural amenities of the region is particularly important as several resources in the city are sensitive and vulnerable to degradation or loss if impacted beyond their capacity to recover. Water features are among the highest profile natural amenities within the city. Brown’s Creek and the St. Croix River are particularly valuable. The St. Croix River is part of the National Scenic River system and draws visitors from throughout the region for boating, fishing, and other recreation activities along the river, river bluffs, and corridor. Brown’s Creek is one of only seven DNR designated trout streams in the seven county Metro Area; this spring-fed stream supplies the cold, clean water necessary for trout habitat and is particularly vulnerable to degradation resulting from land use changes. In addition, the springs that feed the creek often support unique, high quality wetland areas that have the potential to host rare or uncommon plant and animal species (e.g., native mussels. Other important water features include two lakes—Long Lake, and Lily Lake—and the many wetlands found within the city including Lake McKusick. [The DNR classifies Lake McKusick as a wetland. However, residents of Stillwater refer to it as a lake. Therefore, it will be referred to Chapter 3 Contents Introduction ........................3-1 Goals & Objectives ...................3-2 Review of Existing Natural Resources ..3-3 Water Resources .....................3-9 Natural Areas Protection Resources and Best Practices ...........................3-17 Recommendations for City Code Revisions for Natural Resource Protection ......3-22 3-2 PLAN OF STILLWATER Chapter 3 : Natural Resources as “Lake McKusick” throughout this chapter, even though technically it is classified as a wetland.] Goals & Objectives The City of Stillwater worked with its citizens, City Council, commissions and CPAC to develop natural resource goals with supporting objectives. The goals and objectives are the foundation of the Natural Resource Plan, as they define what the community envisions its future to become. Natural Resource Goals Goal 1. Create a natural resource open space system that preserves, protects or restores environmental resources within the City of Stillwater. Objectives 1. Create a natural resource open space system that preserves, protects or restores environmental resources within the City of Stillwater. 2. Preserve, protect and/or restore natural features including: ravine areas, shorelands and blufflands, stands of trees as well as individual heirloom trees, slopes, wetlands and wildlife habitat areas. Goal 2. Use the natural resource open space system to connect trails, open spaces, parks, activity centers and neighborhoods. Objectives 1. Maintain buffering and visual separation between developed areas and adjacent semirural areas. 2. Preserve key scenic roadways, corridors and features and protect the visual beauty and semirural character of the road sides. 3. Coordinate scenic route improvements with roadway improvements. Goal 3. Protect and enhance the St. Croix River, lakes and streams within the City of Stillwater, as well as their shorelines, as natural open space systems and recreation resources. Objectives 1. Encourage natural drainage systems to maintain the natural character of ravines and waterways. 2. Limit controlled public access to sensitive habitat areas or areas that could be impacted by public access. Goal 4. Provide opportunities for enjoyment of natural resources within all areas of the community. Objectives 1. Identify and protect neighborhood open space sites of aesthetic, recreational or natural resources value in preparing neighborhood plans. 2. Encourage the City of Grant and Stillwater Township to use the rural cluster concept in areas adjacent to the City of Stillwater to maintain open space/recreation opportunities. PLAN OF STILLWATER Chapter 3 : Natural Resources 3-3 Review of Existing Natural Resources Natural areas According to the original land survey notes (compiled in Minnesota between 1853 and 1856) at the time of European settlement, the vegetation of what is now eastern Washington County was comprised primarily of oak openings and barrens. This area also included small intrusions of Big Woods-Hardwoods (oak, maple, basswood and hickory) and prairie. Based on these notes, it is apparent that the city of Stillwater supported large areas of Oak Opening vegetation along with Big Woods-Hardwoods in the southwest, and prairie in the southeast portion of the city along the St. Croix River corridor. Today, examples of this historic vegetation (as identified by the DNR’s Minnesota County Biological Survey (MCBS), and by the Natural Resources Inventory (NRI)) are preserved in locations scattered throughout the city. Specific sites identified by the MCBS are as follows: • One Shrub Swamp • One Mixed Hardwood Swamp Seepage Subtype • Two Maple-Basswood Forests (East Central) • Three Oak Forests (Central) Mesic Subtype The NRI also identified several high quality natural areas. The majority of these are scattered throughout the city and include wetlands or wetland complexes and their surrounding upland areas. In addition, a number of high quality forest remnants are found within the city. The MCBS data for Stillwater also lists rare plants and animals found during the assessment, which include: • Bald Eagle (Haliaeetus leucocephalus) nesting site • Mussels Sampling Site • Colonial Waterbird Nesting Site for Great Blue Herons • Rare plant occurrence of Kitten-tails (Besseya bullii) These are among the defining features for Stillwater’s natural resources, and when combined with the semi-natural areas and water features described below, they form important linkages in the DNR’s Metro Conservation Corridors Minnesota Land Cover Classification System (MLCCS) Land cover data has been collected as part of the Minnesota Land Cover Classification System (MLCCS) managed by the Minnesota Department of Natural Resources. This inventory identifies the types and amounts of land cover, vegetation and impervious surfaces, and is very useful in water and natural resources management. MLCCS data is available for the entire city and is shown in Figure 3.1. MLCCS classifies the “natural community” quality into six categories: • Highest Quality Natural Community • Good Quality Natural Community • Moderate Condition Natural Community • Poor Condition of Natural Community • Native Species Present in an Altered/Non- Native Plant Community • Altered/Non-Native Plant Community Natural areas are dominated by native vegetation. Altered/Non-Native Plant Community Areas are areas of land not subject to active use, and which are not dominated by vegetation native to Minnesota. Examples include fallow pasture or crop land which has been retired, degraded wetlands dominated by reed canary grass or other invasive species, and secondary growth or disturbed woodlands, typically dominated by boxelder, green ash, and/ or basswood. These areas still can offer significant benefit for wildlife and for water quality protection and often form important buffers around and connections between remnants of native habitat. As seen on Figure 3.1, these form a significant percentage of the open space and undeveloped lands within the city. Sites within the greenway corridors should be considered high priority for restoration. 3-4 PLAN OF STILLWATER Chapter 3 : Natural Resources Steep Slopes Ancient geologic activity in the region created the predominant land forms in modern day Stillwater. The most recent glaciers left behind the St. Croix moraine creating a band of rolling hills. During the final retreat of the glaciers, meltwater flooded the St. Croix River for many years. The river cut downward, forming the cliffs and bluffs of the river valley. Side streams also cut downward to meet the new riverbed, creating the deep ravines visible in Stillwater today. Exposed bedrock, steep slopes and groundwater springs are common features in this area. Areas of steep slopes are shown on Figure 3.2. Soils The soils of eastern Washington County around the Stillwater area are predominantly undulating to steep, well drained, medium and moderately coarse textured soils. According to the Soil Survey of Washington and Ramsey County (USDA, 1980) the dominant soil types within the City of Stillwater include Urban Land-Kingsley Complex, Santiago, Kingsley and Antigo series. The USDA separates all soil types into Hydrologic Soil Groups, depending on how well they drain. A map of hydrologic soil groups is shown in Figure 3.3. The hydrologic soil groups are categorized as follows: • Group A is sand, loamy sand or sandy loam types of soils. It has low runoff potential and high infiltration rates even when thoroughly wetted. They consist chiefly of deep, well to excessively drained sands or gravels and have a high rate of water transmission. • Group B is silt loam or loam. It has a moderate infiltration rate when thoroughly wetted and consists chiefly or moderately deep to deep, moderately well to well drained soils with moderately fine to moderately coarse textures. • Group C soils are sandy clay loam. They have low infiltration rates when thoroughly wetted and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine structure. • Group D soils are clay loam, silty clay loam, sandy clay, silty clay or clay. This HSG has the highest runoff potential. They have very low infiltration rates when thoroughly wetted and consist chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface and shallow soils over nearly impervious material. NEALAVENPARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAVECUR V E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MAI N S T SSAINTCROIXTRL N MAINSTNS T O N E B R I D G E T R L N WILKINS ST W MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENFAIRY F AL L S R DNNORTHLANDAVESAI NTCROI XTRL NMCKUSICK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake St.CroixRiver¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 µ0 2,000 4,0001,000 Feet City Limit Wetland MN DNR Biodiversity Ranking Outstanding High Moderate Below Natural Community Quality Highest Quality Natural Community Good Quality Natural Community Moderate Condition Natural Community Poor Condition of Natural Community Native Species Present in an Altered/Non-Native Plant Community Altered/Non-Native Plant Community Figure 3.1: Natural Resource Features NEALAVENPARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAVECURV E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MAI N S T SSAINTCROIXTRL N MAINSTNS T O N E B R I D G E T R L N WILKINS ST W MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENFAIRY F AL L S R DNNORTHLANDAVESAI NTCROI XTRL NMCKUSI CK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake St.CroixRiver¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 µ0 2,000 4,0001,000 Feet City Limit Slopes 12% to 18% Slopes 18% to 24% Slopes 24% or more Figure 3.2: Steep Slopes Figure 3.3: Hydrological Soil GroupsNEALAVEN PARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAVECURV E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MAI N S T SSAINTCROIXTRL N MAINSTNS T O N E B R I D G E T R L N WILKINS ST W MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENFAIRY F AL L S R DNNORTHLANDAVESAI NTCROI XTRL NMCKUSI CK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake St.CroixRiver¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 µ0 2,000 4,0001,000 Feet City Limit Hydrologic Soil Group A A/D B B/D C C/D This page intentionally left blank. PLAN OF STILLWATER Chapter 3 : Natural Resources 3-9 Water Resources Surface Water The city has a number of surface water resources. Defining resources include Long Lake, Lily Lake, Lake McKusick (technically a wetland), St. Croix River, and Brown’s Creek. The St. Croix River is the eastern boundary of the city while Brown’s Creek and its tributaries skirt portions of the city’s northern and western boundaries. Lily Lake is found in the south-central portion of Stillwater while Long Lake is located in the southwestern portion of the city and Lake McKusick is near the center of the city. The St. Croix River is a very popular attraction for activities such as fishing and boating. Brown’s Creek and its tributaries compose an array of wildlife and fisheries corridors which ultimately flow into the St. Croix River. The city’s 2018 Surface Water Management Plan has a detailed narrative of the rivers, streams, lakes and wetlands. Public Waters The “Public waters” designation includes lakes, rivers, trout streams and other bodies of water that meet the standards described in Minnesota Statutes, Section 103G.005 , as well as wetlands classified as public water wetlands. Public waters wetlands include all Type 3, Type 4, and Type 5 wetlands that are 10 acres or more in size in unincorporated areas or 2 ½ acres or more in size in incorporated areas. These sites provide public value for recreation, water quality or water supply, wildlife habitat, or are publicly owned. The DNR has regulatory authority over these areas, and specific rules are in place regarding the need for a permit or license to cross or otherwise impact these areas. The St. Croix River and Brown’s Creek are public watercourses. Long Lake and Lily Lake are public water lakes. Lake McKusick, South Twin Lake, Jackson WMA, Brick Pond, and six other un-named wetlands are public waters wetlands. Figure 8 in the Surface Water Management Plan identifies these waters within the city. St. Croix River One of Stillwater’s defining characteristics is its proximity to the St. Croix River. In 1972, Congress added the St. Croix River to the national and scenic river system, known as the Lower St. Croix National Scenic Riverway. The Lower St. Croix National Scenic Riverway extends 52 miles from St. Croix Falls/Taylor Falls to the confluence with the Mississippi River at Prescott/Point Douglas. This stretch of the river is jointly managed by the National Park Service (NPS), Minnesota Department of Natural Resources, and Wisconsin Department of Natural Resources. According to the U.S. Fish and Wildlife Service, “The St. Croix River watershed is the premier mussel watershed of the Upper Mississippi River, and one of the premier mussel watersheds of the world.” According to the DNR’s mussel expert, cities have a role in protecting this mussel through surface water management, especially smart salting practices. The Comprehensive Plan recognizes the following resources as a guide in helping manage this presentee riverway: • Lower St. Croix Cooperative Management Plan • Landowner’s Guide to the Lower St. Croix Riverway 3-10 PLAN OF STILLWATER Chapter 3 : Natural Resources Wetlands Wetlands provide a number of valuable services to the community, including natural flood control, filtering, cleaning, and supplying water for both downstream water bodies and groundwater sources, and creating valuable habitat for fish, amphibians, waterfowl, birds, and other wildlife. Economically, they are an amenity in many developments and can provide visual and spatial buffers between homes. The State of Minnesota and the Federal Government recognize the values that wetlands provide, and have created a series of rules that protect wetlands. In the State of Minnesota, nearly all wetlands are protected by the Wetland Conservation Act. Understanding the location of and providing adequate protection for these resources is an important consideration. There are several sources of information that can help in a preliminary determination of whether wetlands are present on a site, as described below. In all cases a review by an experienced wetland professional is recommended and in some cases required, to make a final determination regarding the presence or absence of a wetland and determine the legal boundaries of any wetlands. Appropriate permits are required prior to any activities which fill, drain, or otherwise impact a wetland. National Wetlands Inventory The National Wetlands Inventory (NWI) is a national assessment of wetland resources, conducted by the United States Fish and Wildlife Service between 1988 and 1992 within the state of Minnesota. The NWI survey was based strictly on aerial photography reconnaissance and interpretation, and may be less accurate than some of the other sources. However, the NWI coverage is useful in giving an estimate of the extent (i.e. approximate geographic location) and type (i.e. system, hydrologic regime, and predominant vegetation types) of wetlands within the city. City of Stillwater Wetland Inventory and Assessment The city conducted a detailed wetland inventory in 2006. It included wetlands located within the three different watershed organizations or watershed districts within the city. These included Brown’s Creek Watershed District (BCWD), the Middle St Croix Watershed Management Organization (MSCWMO), and Carnelian-Marine-St. Croix Watershed District (CMSCWD). The assessment focused on NWI wetlands which had not previously been checked by the watershed organization in which they occur. The exception was wetlands within golf courses which were either converted to water hazards or which appeared to be filled, and sites which were clearly storm ponds and removed from the inventory by city staff. These wetlands were then field verified and assessments were conducted on each wetland. Qualitative rankings were given based on criteria established by MnRAM and stormwater susceptibility. Wetlands were then assigned to different management classes according to the criteria for the governing watershed to establish rules for wetland protection and management based on the functions and values provided by each wetland. A map of the wetlands and their rankings is seen on Figure 3.4. NEALAVENPARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAVECURV E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MAI N S T SSAINTCROIXTRL N MAINSTNS T O N E B R I D G E T R L N WILKINS ST W MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENFAIRY F AL L S R DNNORTHLANDAVESAI NTCROI XTRL NMCKUSI CK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake St.CroixRiver¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 µ0 2,000 4,0001,000 Feet City Limit Watershed Management Districts Wetlands Brown's Creek WD Preserve Manage 1 Manage 2 Manage 3 Middle St. Croix WD A Preserve B Maintain C Manage Carnelian-Marine-St. Croix WD Pending General Storm Pond / Golf Course Drained / Filled / Non-W etland No Access Lakes & Rivers Figure 3.4: Water Resources - Wetlands !(!( !(!(!(!( !(!(!( !(!(NEALAVENPARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAVECURV E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MAI N S T SSAINTCROIXTRL N MAINSTNS T O N E B R I D G E T R L N WILKINS ST W MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENFAIRY F AL L S R DNNORTHLANDAVESAI NTCROI XTRL NMCKUSI CK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake St.CroixRiver¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 µ0 2,000 4,0001,000 Feet City Limit Groundwater Dependent Stream Shrub Fen Black Ash Swamp Seepage Subtype Mixed Hardwood Seepage Swamp Mixed Hardwood Swamp - Seasonally Flooded Sensitive Recharge Area Figure 3.5: Groundwater Sensitive Resources PLAN OF STILLWATER Chapter 3 : Natural Resources 3-13 Groundwater Three main bedrock aquifer units are found in the Stillwater area. The uppermost bedrock aquifer is the Prairie du Chien-Jordan aquifer. This aquifer is comprised of the Prairie du Chien dolomite overlying the Jordan sandstone. High capacity wells are typically open to the Jordan formation, since the Jordan sandstone represents the portion of the aquifer with the highest permeability. Yields from Jordan wells typically range from 1000-2000 gpm per well. The next aquifer in the stratigraphic sequence is the Franconia-Ironton-Galesville (FIG) bedrock aquifer. Yields from the FIG aquifer are typically under 1000gpm per well, but may be much lower in the Stillwater area. The highly variable nature of this aquifer across the metro area makes performance hard to determine without site-specific aquifer pumping data. Performance of the FIG aquifer in the eastern metro tends to be somewhat less than seen in areas of the northwest and southwest metro. The lowest bedrock aquifer unit, which underlies the FIG aquifer, is the Mt. Simon bedrock aquifer. The Mt. Simon aquifer can yield water supply in the range of 700-1500gpm per well. At present, the Minnesota DNR is restricting the development of new wells in the Mt. Simon aquifer in the seven county metro area in order to prevent excessive withdrawals from this aquifer. The deep setting of this aquifer in the Twin Cities means that recharge to the aquifer is often slower than seen in shallower aquifers, such as the Jordan aquifer. Wells, if over-pumped, can often exceed the ability of the aquifer to become recharged, causing widespread drawdown of water levels within the aquifer. Cities that already have wells open to the Mt. Simon aquifer (such as Stillwater Well No. 1) are allowed to continue use of those wells, though they may not be allowed any increases in appropriations from those wells. Besides the bedrock aquifers, shallow drift aquifers are present within portions of the Stillwater area. Sample well logs from the Stillwater area show the drift aquifer does not appear to be fully saturated in all locations. Potential yields from drift aquifer wells may be sufficient for small capacity private wells, but would likely not be sufficient to support Floodplains Floodplains are regulated by the city’s Floodplain Overlay District to control development in flood prone areas and minimize losses. The Federal Emergency Management Agency (FEMA) administers the Federal Insurance Rate Maps (FIRM) for jurisdictions. The current FIRM maps were issued in 1982/84. These maps determine boundaries for purposes of flood insurance. These could vary from the 100 year or 500 year flood boundaries as determined by local watersheds. FEMA expects to release updated FIRM maps for Washington County in the near future. 3-14 PLAN OF STILLWATER Chapter 3 : Natural Resources on groundwater discharge to maintain flows and temperatures ideal for trout habitat. Overuse of the Jordan aquifer in areas near the stream could compromise stream quality and diminish remaining trout habitat. Greenway Corridor A greenway is defined as a “privately or publicly owned corridor of open space which often follows natural land or water features and which is primarily managed to protect and enhance natural resources”. However, greenways can and often do incorporate active or passive recreational trails, active recreational spaces (such as athletic fields or golf courses), and other public open spaces that may provide rudimentary ecological functions and values. The Minnesota DNR developed a Metro Conservation Corridors analysis and map to help counties and local governments prioritize areas for conservation and restoration. This analysis identifies high-quality natural areas, existing protected and/or public open space areas such as designated wildlife management areas, natural corridors such as stream courses, and connecting areas between these features. The assessment identifies a corridor within Stillwater located along the St. Croix River and Brown’s Creek. If gaps and missing connections within the greenway can be filled, the greenway corridor will provide a critical foundation to help the ecological systems of Stillwater and the region adapt to changing land uses and long-term, to the pressures brought by global climate change. A complete Greenways Corridor system would form the backbone for natural resources conservation within the city, and has implications for natural resources conservation across the region. Through a multi-faceted approach, the city is creating a Greenway Corridor through park dedication fees being used for natural resource preservation, and establishing buffers around lakes, streams, and wetlands, as seen in Figure 3.6. This figure demonstrates the creation and preservation of greenways throughout the community. high capacity municipal wells. Management of groundwater in the Stillwater area should be focused on prevention of human-caused contamination from spoiling future water supplies. Figure 3.5 displays Sensitive Groundwater Resource areas including sensitive recharge areas. Care should be taken around wetlands, fens, and other natural features that recharge the groundwater. The Jordan aquifer is heavily relied upon to supply the municipal water supply wells. As such, this aquifer should be the focus of efforts to prevent impacts from contamination. The Jordan aquifer is considered to be relatively high in vulnerability and therefore is likely to become contaminated if spills or leaks go unchecked. The vulnerability of the Jordan aquifer is witnessed by widespread contamination in the Baytown area, south of Stillwater. While this contamination is unlikely to impact Stillwater’s wells, it demonstrates that a single point source can be responsible for contaminating large areas of the Jordan aquifer. At present, the City of Stillwater is developing part two of their Wellhead Protection Plan in order to manage potential sources of contamination. As future wells are added to the city’s water supply system, the Wellhead Protection Plan will need to be expanded to encompass the areas that supply these wells. A side benefit of Wellhead Protection Planning is that it raises awareness in the community of the importance of groundwater protection in general. Overall efforts to protect the city’s water supply wells should also result in greater protection to the aquifers that supply the area’s private wells. Also, any efforts to expand the well field and/ or increase the appropriations from the current municipal wells will require working in cooperation with the DNR to ensure that the impacts to the aquifer fall within acceptable levels. While the Jordan aquifer is thought to be highly productive in the Stillwater area, excessive withdrawals from the aquifer might impact sensitive natural resources that rely on groundwater. One example is the Brown’s Creek trout stream, which runs through the Stillwater area. This trout stream is dependent NEALAVENPARIS AVE NGREELEYSTSOSGOOD AVE NCROIXWOODBLVD WASHINGTONAV E CURV E C RES T BLVD W 60TH ST NSTILLWATERBLVDN OWENS ST NO RLEANS ST W PINE ST W 2ND ST N7 5 T H S T N B E A C H RDN3RD ST S6TH AVE SC H E S T N U T S T E MA I N S T SSAINTCROIXTRLNMAINSTNS T O N E B R I D G E T R L N MCKUSICK RD N OLIVE ST W MYRTLE ST W ORLEANS ST E CHURCHILL ST W DELLWOOD RD N LAUREL ST W P IN E S T EMANNINGAVEN 62ND ST N NORELLAVENNORTHLANDAVESAI NTCROI XTRL NMCKUSI CK RDB O O M RDBrick Pond South Twin Lake McKusick Lake Long Lake Lily Lake S t. C r o i x R i v e r ¬«21 ¬«15 ¬«66 ¬«12 ¬«23 ¬«24 ¬«5 ¬«55 ¬«64 ¬«5 ¬«11 ")36 ")95 ")95 ")5 ")96 Anez Ridge Park Benson Park Bergmann Park Browns Creek Natural Preserve Browns Creek Park Creekside Park Croixwood Open Space Bridgeview Park Boutwell Cemetery Park Heritage Park Lakeside Park Legends Gazebo Legends Park Liberty Square Lily Lake Park Long Lake Natural Area Long Lake Open space Lowell Park McKusick Lake Trail & Dike McKusick Park Meadowlark Park Millbrook Community Park Nightingale Park Northland Park Pioneer Park Prairie Park Public Works Park Ramsey Grove Park Schulenberg Park Settlers Park St. Croix Valley Recreation Center Staples Field Sunrise Park Teddy Bear Park Triangle Park Washington Square Millbrook Neighborhood Park Fairy Falls Park Future Aiple Park Kolliner Park Oak Glen Golf Course Stillwater Country Club Stillwater Area Dog Park µ0 2,000 4,0001,000 Feet City Limit Wetland 25' Lake/Wetland Buffer 100' Lake/Wetland Buffer Parks Open Space and Natural Area Regionally Significant Ecological Area Figure 3.6: Greenway Corridors This page intentionally left blank. PLAN OF STILLWATER Chapter 3 : Natural Resources 3-17 As much as possible, development within the greenway—whether city greenway or DNR Metro Wildlife Corridor-- should use conservation design strategies, park dedication, and the strategic siting of open space and natural area parks to develop and improve habitat quality and connectivity within the greenways. Strategies to avoid parcelization and fragmentation of existing natural areas into smaller sections are especially important for maintaining ecological function of the natural areas. This protection will be further supported with the use of the Multi-Purpose Greenway Corridor and the creation of subsequent zoning protection as discussed in the Land Use Chapter. Natural Areas Protection Resources and Best Practices As demonstrated above, Stillwater is home to many high value natural resources. As the city grows and redevelops, protection of these resources is critical. There are a variety of tools and strategies available to the city to manage and protect its natural resources, which are discussed below. Sustainability Sustainability refers to the concept of using practices and strategies on the land that can be maintained over time without damaging the environment; the intent is to balance near-term interests with the protection of the interests of future generations, to maintain and potentially improve environmental quality. Sustainability can be achieved through a variety of strategies, each using natural resources preservation as the guiding principle, while still allowing use of the land. Low Impact Development LID is a sustainable stormwater management strategy that focuses on managing stormwater locally, using features such as swales, green roofs, constructed wetlands, pervious pavement, and rainwater gardens to infiltrate runoff rather than relying solely on a system of pipes and stormponds. It has significant water quality benefits and can effectively manage small to moderate rainfall events, depending on the LID design. Adding a LID ordinance to city code could benefit water resources. Conservation Design Subdivisions Conservation Design Subdivision is the practice of designing subdivisions to minimize their impact to the environment by using LID strategies, and thoughtful siting of homes and infrastructure to maintain the ecological integrity and function of the landscape. Once a parcel evaluation has been completed to identify areas suitable for low-impact development, subdivisions are designed to allow for more compact development or clustering of 3-18 PLAN OF STILLWATER Chapter 3 : Natural Resources homes in smaller areas and retain larger areas of common, open space. If thoughtfully implemented, Conservation Design can foster a sense of neighborhood and community that is sometimes lost in large lot developments, and it is an effective choice for maintaining natural resource quality while allowing development. For example, in Conservation Design quality forest areas would be left largely intact, and construction activities would occur in semi-natural areas or former agricultural lands. This strategy is appropriate in areas with remnant natural areas, and is especially important for developing and maintaining connections in the Greenway Corridors. Park Dedication Ordinance The City’s Park Dedication ordinance can be an effective strategy for developing and maintaining a parks and open space system within the city. The ordinance acknowledges the value that parks and open space provide for area residents, and requires that any new development include a specified amount of parks and/or open space within it. In lieu of land, a specified fee may be required instead, either based on the total area of land or on the number of proposed units. Fees would then be assigned to a dedicated parks fund and used for the permanent acquisition and development of parks. This can be a very effective tool for developing resources for parks, and allows the city flexibility in determining how and where parks are created. For example, if a proposed development is not impacting any significant natural areas and is not within an identified greenway corridor or open space, the park dedication fee may allow the city to acquire areas that help achieve the goal of developing an open-space system. Similarly, for developments proposed within the open space system, natural areas or restorable areas within the system could be required as set-aside for parks and open space. Shoreland Ordinance The city has a Shoreland Management Overlay District to protect the quality of its lakes and streams. The purpose of the ordinance is: • regulate the size of a building lot; • establish the length of water frontage suitable for building sites; • discourage the alteration of shorelands of public waters; • control alterations of the natural vegetation and the natural topography along wetlands and shorelands, conserve and develop natural resources; and to • maintain a high environmental quality. Further details can be found in the Sec. 31-402 of the city code. Parcel Evaluation Parcel evaluation is a useful strategy for identifying areas where methods such as cluster development or Conservation Design subdivision may be appropriate as a way of protecting priority natural resources. One potential approach is to identify parcels with development or redevelopment potential above a specified size threshold (for example, 10 acres) and determine which of these parcels intersect with priority natural resource features. An additional level of planning would be to consider these factors and overlay them with the DNR identified greenway corridors. This may facilitate planning by allowing the city to focus conservation strategies within a defined area (the greenway corridors). Wellhead Protection Plan The City of Stillwater’s Part 1 Wellhead Protection Plan was approved by the Minnesota Department of Health on November 16, 2017 and the Metropolitan Council on March 7, 2018. The city is currently in the process of completing their Part 2 Wellhead Protection Plan, which is scheduled for final review and adoption in August 2019. The Wellhead Protection Plan covers the seven primary !. !. !.!.!. !.!.!.!. !.!. !.!.!.!. !. !. "/ !.!. "/ "/ "/ !. "/ "/ "/ "/ "/ "/ "/"/ "/ "/ D oc u me nt P ath: K :\01 0 1 00 -0 00\G IS\M a p s\S WM P \Fig u re 1 1_G roundwater.mxd Date Saved: 11/9/2017 10:54:32 AM Legend Stillw a te r Boundary We llh e ad Prote c tion Areas Water Appropriations #0 Ma jo r Cr op Irrigation "/N on -C ro p Ir rigation !.Wa ter works DWSM A W ell Vul nerability Ve ry H igh H igh Mo de rate Lo w Ve ry Low Figure 11 - Groundwater Protection Local Su rf a ce W ater Mana gement Plan 0 1,8 00Fe et ¯ 1 i n ch = 1,800 fee tDate: 11/10/2017 St. C r oix R iv er Lily L ak e La k e M cKusic k Lo n g L ak e Sou th Tw in Lak e Bro wn s Creek Figure 3.7: Drinking Water Supply Management Area This page intentionally left blank. PLAN OF STILLWATER Chapter 3 : Natural Resources 3-21 water supply wells (Well Nos. 1, 5, 6, 8, 9, 10, and 11) currently online and serving the city’s water supply system, as seen in Figure 3.7. All wells obtain their water from the Jordan sandstone aquifer, with Well No. 1 also open to the Franconia-Ironton-Galesville and Mt. Simon aquifer units. The Jordan aquifer that underlies the identified Drinking Water Supply Management Area (DWSMA) for the seven wells was ranked as being “vulnerable” to contamination. That means there does not appear to be sufficient geologic protection between the land surface and the Jordan aquifer to impede vertical infiltration of contaminants into that aquifer. While some areas of low permeability soil or sediment may be present, they are not present in sufficient thickness or aerial extent to warrant a non-vulnerable ranking. Management efforts outlined in the Part 2 Wellhead Protection Plan aim at managing all potential sources of contamination that could impact the aquifer, including storage tanks, other wells, septic system, hazardous waste generators, row crop agriculture, and any other point or non- point pollution sources. As the City of Stillwater’s water supply system expands to include more wells, the Wellhead Protection Plan will need to be updated in order to delineate DWSMAs for those new wells, assess aquifer vulnerability for those new DWSMAs, and develop management strategies to protect the aquifer(s) feeding the city’s wells. Wetland Protection The city’s 2018 Surface Water Management Plan (SWMP) provides guidelines for wetland management and protection from stormwater runoff. Section 3.4 in the 2018 SWMP compares the rules from the three watersheds with current city ordinances. Although most of the watersheds regulate bounce and phosphorus levels and have buffer rules, there are gaps between the watersheds and within the city that can be filled to maintain consistency within the city. 3-22 PLAN OF STILLWATER Chapter 3 : Natural Resources Recommendations for City Code Revisions for Natural Resource Protection Based on the discussion of Stillwater’s natural resources and strategies for resource protection included in this Chapter, several potential revisions for Stillwater’s city code are suggested. These revisions are listed below. Include Natural Resource Data in Preliminary Plat The city could require project proposers to identify all natural resource data from the NRI as part of the data submission for a project. This data could then be used to identify any necessary setbacks or alignments of potential greenway corridors. Include Dedication of Natural Resources Areas as Parkland The city could consider ordinance amendments to require developers to dedicate the natural resource areas identified on the NRI maps as open space or parks if they are located within the proposed development area. Dedication of these areas may offset at least a portion of the parkland dedication requirement. Conservation easements are another tool that can be used to protect these resources. If the size of the natural resource area contained on the site is greater than the land dedication required by ordinance, the city could allow additional density on other portions of the site that do not contain natural resource areas equivalent to the density lost from the additional dedication. The city may also consider adding language to the park dedication ordinance that specifically states park dedication funds may be used for the purposes of ecological restoration (restoring native plant communities) on lands available to the public. Such activities could be considered a form of park “development”. This would allow for necessary active management of purchased or existing natural areas. Natural Resource Inventory The MLCCS Data provides the city with extensive data related to the location and quality of natural resources in the city. The city can use this information as a basis for updating its current environmental ordinances as necessary, or for developing new approaches for protecting and enhancing its natural resources. Future growth, changes in land use, and development of infrastructure can impact the health and function of natural communities and natural systems. The city can use its zoning and subdivision controls to avoid or minimize these impacts, and provide incentives for developers and landowners to protect or restore natural resources. Education and Outreach The City of Stillwater should consider pursuing education and outreach opportunities for its residents to increase awareness of Stillwater’s natural resources and the importance of resource protection. Intergovernmental Coordination Intergovernmental coordination is critical for optimal ecological function, as natural resource areas typically cross jurisdictional boundaries and because the actions of one community often impact a much larger ecosystem encompassing many surrounding communities. Coordination with other jurisdictions, including neighboring communities and appropriate watershed districts, provides opportunity for shared financial resources, as collaborative, cross-jurisdictional efforts often have better grant eligibility for conservation and planning projects. PLAN OF STILLWATER Chapter 3 : Natural Resources 3-23 Consider Gross Density Calculation for Developments with Natural Resource Areas Protection of valuable natural areas may require preventing development on certain pieces of land. In order to ensure efficient urban development and preserve the rights of landowners while protecting natural resources, density transfers or “gross density” calculations should be preferred when reviewing subdivision development plans. The city could adopt regulations that require that all high-value natural areas, wetlands, steep slopes, their related buffers and setbacks, and other sensitive resources be put under easement while allowing the same amount of density overall for the development. Environmental Protection Overlay Zone Overlay districts are commonly used in zoning ordinances to identify special areas and requirements applied to these areas. The Stillwater code includes a Shoreland overlay district, a St. Croix overlay district and a Floodplain overlay district. The Minnesota Environmental Quality Board has suggested an option of using a broader overlay district called a Sensitive Natural Environment Areas overlay district for protecting and conserving significant natural resources in the community. This overlay district can provide protection for a full range of natural community types—woodlands, prairies, wetlands, and shorelands. It could reduce the need for separate park dedication, or buffer protection elements discussed. The areas may also include natural resource corridors or greenways identified in the community. The adoption of an environmental protection zone overlay ordinance requires that the community’s resources have been inventoried. Stillwater’s Natural Resource Inventory and MLCCS data meets this need. In some cases, two zones are established—Environmental Protection Zones with the highest level of protection for high quality resources, and Environmental Conservation Zones for resources of somewhat lower quality that require a lower standard of protection. The protection zone or zones would be mapped on official city zoning maps, just as the Shoreland and Floodplain overlay zones are mapped. The environmental protection zone ordinance then provides requirements or standards for development within these zones. Such requirements may include the following: • Setbacks or buffers from the edge of the sensitive area • Construction management practices to limit disturbance or damage • Limits to vegetation removal • Prohibition or limitation of development within the zones by regulating disturbance, lot sizes, densities, etc. • Limit to impervious surface coverage Given the number and diversity of high quality natural areas identified in the city’s Natural Resource Inventory, an overlay ordinance of this type offers a way to provide protection to this range of resources rather than using multiple ordinances to address woodlands, wetlands, and other types of natural resources. Other Tools for Protection and Management of Natural Areas Ordinances are mainly a regulatory approach for protecting and managing natural resources. They can also provide incentives to natural resources protection. Many communities use a combination of regulations and incentives in protecting and managing natural resources. The regulatory approach assures that some priority resources will be protected, but is limited by laws that prohibit the “taking” of private property without adequate compensation. The incentive approach may be more politically acceptable in some cases than the regulatory approach, and may be more viable when potential “taking” is an issue. In addition to changes in existing ordinances or adoption of new ordinances, the city can consider encouraging city residents to protect the natural resources on their properties by: • Providing information and education to 3-24 PLAN OF STILLWATER Chapter 3 : Natural Resources This page intentionally left blank.