2014 Annual Water Quality Report

Transcription

1 WENCK File #B May Annual Water Quality Report Prepared for: Shingle Creek and West Mississippi Watershed Management Commissions 3235 Fernbrook Lane Plymouth, MN shinglecreek.org Prepared by: WENCK Associates, Inc Pioneer Creek Center Maple Plain, MN Phone: Fax:

2 Table of Contents 1.0 INTRODUCTION Background Objectives TMDLs and implementation plans WEST MISSISSIPPI OUTFALL MONITORING Overview precipitation Hydrology Water quality Summary and recommendations SHINGLE CREEK STREAM MONITORING Overview Precipitation Hydrology Water quality Summary and recommendations CITIZEN ASSISTED LAKE MONITORING PROGRAM Overview Water quality standards CAMP MonItoRing Results YEAR TMDL REVIEW LAKE MONITORING Overview Lake description Water quality monitoring Schmidt Lake Water Quality Bass Lake Water Quality Vegetation surveys Schmidt Lake Survey Results Bass Lake Survey Results BIOLOGICAL MONITORING Overview Introduction Stream Macroinvertebrate Monitoring Findings Monitoring Discussion Wetland Monitoring Monitoring May 2015 i

3 Table of Contents (Cont.) TABLES Table 1-1. Impaired Waters in the Shingle Creek watershed Table precipitation measured at the New Hope weather station Table precipitation measured at the New Hope weather station Table 3-2. Shingle Creek annual flow volumes and runoff depths Table 4-1. State of Minnesota water quality standards Table 4-2. Shingle Creek lakes by depth Table CAMP summer average monitoring results Table 5-1. Plant species frequency of occurrence in Schmidt Lake Table 5-2. Plant species frequency of occurrence in Bass Lake Table 6-1. Park Center High School Site # Table 6-2. Lions Park, Brooklyn Center Table 6-3. Mattson Brook Site # Table 6-4. Webber Park - Site # Table 6-5. North Hennepin Community College Site # Table 6-6. Boone Avenue - Site # Table 6-7. Brookdale Library Table 6-8. Wetland monitoring site BP-4 Oxboro Ponds Table 6-9. Wetland monitoring site BC Table Wetland monitoring site CR Table Wetland monitoring site BP Table Wetland monitoring site BP Table Wetland monitoring site BP Table Wetland monitoring site BP Table Wetland monitoring site BP Table Wetland monitoring site PL Table Wetland monitoring site CH Table Wetland monitoring site BC FIGURES Figure 1-1. Shingle Creek and West Mississippi stream, outfall and lake sites Figure 1-2. Shingle Creek and West Mississippi biotic and wetland monitoring sites.1-3 Figure 2-1. Oxbow outfall monitoring location and general flow direction Figure th Ave outfall monitoring location and general flow direction Figure minute flow measurements for the Oxbow outfall monitoring site Figure Average daily flow for each Shingle Creek monitoring station Figure Cumulative flow volume for each Shingle Creek monitoring station3-3 Figure 3-3. Annual precipitation and runoff depth for all Shingle Creek monitoring stations Figure DO longitudinal survey results Figure shallow lake CAMP total phosphorus data Figure deep lake CAMP total phosphorus data Figure 5-1. Schmidt Lake 2014 TP, Chlorophyll-a and Secchi depth Figure 5-2. Schmidt Lake historic TP, chlorophyll-a and Secchi Depth Figure 5-3. Bass Lake 2014 TP, Chlorophyll-a and Secchi depth Figure 5-4. Schmidt Lake historic TP, chlorophyll-a and Secchi Depth Figure 5-5. Schmidt Lake early summer (left) and late summer (right) plant biovolume Figure 5-6. Eurasian milfoil and curly-leaf pondweed density in Schmidt Lake May 2015 ii

4 Figure 5-7. Bass Lake early summer (left) and late summer (right) plant biovolume.5-13 Figure 5-8. Eurasian milfoil and curly-leaf pondweed density in Bass Lake Figure 6-1. Wetland monitoring site BP-4 at Oxboro Ponds in Brooklyn Park Figure 6-2. Wetland monitoring site BC-2 in Palmer Lake Park, Brooklyn Center Figure 6-3. Wetland monitoring site BP-5 in Brookdale Park, Brooklyn Park Figure 6-4. Wetland monitoring site BP-6 in Greenhaven Park, Brooklyn Park May 2015 iii

5 Table of Contents (Cont.) APPENDICES Appendix A: Appendix B: Appendix C: Appendix D: West Mississippi Outfall Sampling West Mississippi and Shingle Creek Rating Curves Shingle Creek Sampling May 2015 iv

6 Executive Summary The Shingle Creek and West Mississippi Watershed Management Commissions annually monitor water quality in the lakes and streams of the watersheds. The Commissions technical staff obtains the stream and some lake water quality data while volunteers collect most lake water quality and stream and wetland macroinvertebrate and vegetation data. Water quality in a given year is influenced by the amount of precipitation and the type of precipitation events. Overall, 2014 was an above average precipitation year. Rainfall in April and June were well above average, while July, August, September and October were dry and below average. The timing of events and rainfall intensity also play a part in determining water quality. This annual variability is why ongoing, long-term monitoring is necessary to determine actual trends in the data and what may be considered natural variability. Water quality in Shingle Creek is typical of an urban stream in the Twin Cities metropolitan area, and is dominated by watershed runoff. Continued monitoring of stream water quality will allow us to evaluate the effectiveness of BMPs and provide a baseline for reasonable water quality goals. The lakes in Shingle Creek are typical of urban lakes. Thirteen of the 16 lakes are listed as Impaired Waters due to excess nutrients, and TMDLs and Implementation Plans have been approved for all 13 of the lakes. Three of the lakes are proposed for delisting on the pending 303(d) list of Impaired Waters. The lake TMDLs and the Shingle and Bass Creeks chloride, biotic, and dissolved oxygen TMDLs set forth action plans for improving water quality and biotic integrity in the impaired lakes and streams in the Shingle Creek watershed. May 2015 iii

7 1.0 Introduction 1.1 BACKGROUND Minnesota Administrative Rule Subp.5 requires watershed management organizations to conduct monitoring programs capable of producing accurate data to the extent necessary to determine whether the water quality and quantity goals of the organization are being achieved. The Shingle Creek and West Mississippi Watershed Management Commissions (WMC) began monitoring water quality and streamflow in In Shingle Creek, 12 sites were monitored from , however monitoring was discontinued from Shingle Creek has since resumed on an annual basis at two long-term monitoring sites (SC-0 and SC-3). In 2013, a third stream monitoring site was added near the outlet of Bass Creek (BCP). The West Mississippi WMC monitored water quality and streamflow from at two outfall sites in the Oxbow Creek and Mattson Brook watersheds (Figure 1-1). Results indicated very little flow in these tributaries and no water quality or quantity problems or concerns. Thus, the Commission chose to discontinue monitoring after the 1992 monitoring season. In 2010, the Commission elected to once again monitor water quality and flow at 2-3 outfall monitoring sites per year in the West Mississippi watershed. Thirteen of the sixteen lakes in Shingle Creek are periodically monitored for water quality by volunteers through the Citizen Assisted Monitoring program (CAMP) (Figure 1-1). Seven lakes were monitored through the CAMP program in 2014, including: Pomerleau, Meadow, Upper Twin, Middle Twin, Lower Twin, Crystal, and Success. Additionally, Wenck staff conducted intensive monitoring on Schmidt and Bass Lakes in 2014 as part of the 5-year TMDL review for these lakes. High school volunteers coordinated by Hennepin County Environmental Services (HCES) performed macroinvertebrate monitoring at two locations in 2014 on Shingle Creek and one site on Mattson Brook in the West Mississippi watershed (Figure 1-2). HCES also coordinates wetland monitoring by adult volunteers. In 2014, wetland monitoring was performed at three locations in the Shingle Creek watershed, and one location in the West Mississippi watershed (Figure 1-2). 1.2 OBJECTIVES The Shingle Creek and West Mississippi WMCs have established monitoring objectives to guide their monitoring programs. The following objectives have been established for stream, outfall and lake monitoring both watersheds: To quantify the current status of streams/outfalls and lakes (Shingle Creek only) throughout the watershed in comparison to state water quality standards established for nutrients, turbidity, chloride, bacteria, and other parameters currently regulated by the State. To quantify changes over time, or trends, in stream and lake water quality in the Shingle Creek and West Mississippi watersheds. To quantify the effectiveness of implemented BMPs throughout the watershed for the protection of water quality. May

8 Figure 1-1. Shingle Creek and West Mississippi stream, outfall and lake sites. Note: the stations circled in red were monitored during the 2014 monitoring season May

9 Figure 1-2. Shingle Creek and West Mississippi biotic and wetland monitoring sites. Note: the stations circled in red were monitored during the 2014 monitoring season May

10 1.3 TMDLS AND IMPLEMENTATION PLANS Most of the lakes in the Shingle Creek watershed do not meet state standards for water quality, and are included on the Minnesota Pollution Control Agency (MPCA) 303(d) List of Impaired Waters. The 303(d) list is named after the section of the federal Clean Water Act that requires states to set water quality standards and to assess conditions in lakes, rivers, and streams to determine if those standards are being met. If the standards are not met, a Total Maximum Daily Load (TMDL) study must be completed to identify the course of action needed to restore the resource to meet state standards. Table 1.1 below shows the Impaired Waters in the Shingle Creek watershed. Regional or statewide impairments that affect the watershed are also noted in Table 1.1 and are being sponsored by the MPCA. The Commission has completed or is completing TMDLs for the balance of the impairments. Each TMDL establishes a water quality goal and a pollutant load reduction to achieve that goal. A separate TMDL Implementation Plan sets forth actions that will be undertaken by various stakeholders. Those actions include the continuation and expansion of lake and stream monitoring to assess progress toward the load reductions and water quality goals. Table 1-1. Impaired Waters in the Shingle Creek watershed. Water Resource Impairment Date TMDL Approved 5-year Review Bass Lake Nutrients 9/25/ Cedar Island Lake Nutrients 4/14/ Crystal Lake Nutrients 3/25/ Eagle Lake Nutrients 4/14/ Lake Magda Nutrients 9/30/ Meadow Lake Nutrients 3/23/ Pike Lake Nutrients 4/14/ Pomerleau Lake Nutrients 9/25/ Ryan Lake Nutrients 11/9/ Schmidt Lake Nutrients 9/25/ Upper, Middle, and Lower Twin Lake Nutrients Mercury in fish PFOS in fish PCB in fish 11/9/07 3/27/07 (MPCA) Not yet begun (MPCA) Not yet begun (MPCA) 2014 Shingle Creek Chloride 2/14/ Shingle Creek Dissolved oxygen 11/4/ Shingle Creek Biota-macroinvertebrates 11/4/ Bass Creek Biota-fish 11/4/ Bass Creek Chloride Metrowide in process(mpca) May

11 2.0 West Mississippi Outfall Monitoring 2.1 OVERVIEW Water quality was collected at two outfall locations (Oxbow and 65 th Ave), and continuous flow monitoring was collected at one location (Oxbow) in the West Mississippi watershed in 2014 (Figure 1-1). Located in the City of Champlin, the Oxbow outfall site was first sampled during the West Mississippi monitoring program. When monitoring resumed in 2010, this site was not sampled the first few years because the storm sewer s outfall to the Mississippi River was completely submerged and not accessible to sample. In 2013, an alternative site upstream of where the outfall discharges to the Mississippi at 112th Ave N. was selected for monitoring in 2013 (Figure 2-1). Flow at this site is contained below ground in a 48 inch pipe which is accessible through a 2 foot manhole at 112th Ave N. Most of the Oxbow Creek outfall watershed consists of a series of storm sewer pipes that drain approximately 1,167 acres of land in Champlin. Figure 2-1. Oxbow outfall monitoring location and general flow direction. The 65 th Ave outfall is located in the City of Brooklyn Center at the northeast corner of the Highway 252 and Interstate 694 interchange (Figure 2-2). This outfall drains approximately 590 acres of land in Brooklyn Center which includes runoff from the Regal Cinema and other commercial and industrial land east of Highway 252. Continuous flow monitoring was not collected at the 65 th Avenue outfall site in 2014 due high-flow conditions in the Mississippi River from April until early August. These high flow conditions created backwater effects near the 65 th Avenue outfall location which prevented reliable stage measurements in the outfall pipe and created unsafe conditions for mounting and setting monitoring equipment. However, Wenck staff was able to safely collect water quality grab samples at the 65 th Avenue outfall throughout most of the 2014 sampling season by lowering a weighted bucket into the storm sewer pipe. May

12 Regal Cinema 65 th Ave Figure th Ave outfall monitoring location and general flow direction. 2.2 PRECIPITATION Table 2-1 summarizes monthly precipitation data for the New Hope National Weather Service located in the Shingle Creek watershed (Figure 1-1). Precipitation was well above average in April and June, and was close to average or below average during all other months. Overall, precipitation was 2.89 inches above normal in 2014, which was largely driven by a few large rainfall events in April and June. Table precipitation measured at the New Hope weather station. Month 2014 Precipitation (inches) Monthly Average Precipitation (inches) Departure from Long-Term Average (inches) January February March April May June July August September October November December TOTAL May

13 2.3 HYDROLOGY Reliable stage (water level) was continually recorded from through mid-july through late October at the Oxbow outfall. The flow monitoring equipment was initially installed in mid- April, however the high, intense rainfall events in April and June dislodged the equipment from its mounting bracket on several occasions. Continuous flow was not monitored at the 65 th Avenue outfall in 2014 due to high flow conditions in the Mississippi River until early August. In the fall of 2014, Wenck installed new mounting brackets in both the Oxbow and 65 th Avenue outfall storm sewer pipes. These brackets should be able to withstand the higher flow conditions and allow staff to better monitor flow at both sites in For the Oxbow outfall site, flow was estimated using the measured stage data in the storm sewer pipe and applying Manning s equation for uniform flow. Culvert dimensions and physical parameters were derived from as-built drawings. A Manning s roughness coefficient of was selected as a representative roughness for the concrete pipe (Appendix B). Figure 2-3 shows the 15-minute flow data (hydrograph) for the Oxbow outfall site. Results indicate flow at this site does have a consistent year around base-flow of at least 0.5 cfs, however the site is extremely flashy during storm events. During storm events, the hydrograph rises quickly and typically peaks within 30 minutes of the initial rainfall, then quickly subsides to base-flow conditions within a few hours. This type of flow response is common in smaller urban catchments. Figure minute flow measurements for the Oxbow outfall monitoring site. May

14 2.4 WATER QUALITY Routine water quality sampling for each outfall station consisted of bi-weekly grab samples from May through early November. Three composite storm samples were also collected at the Oxbow site using automated sampling equipment. No composite storm samples were collected at the 65 th Avenue outfall in 2014 due to high levels in the Mississippi River which impeded installation of monitoring equipment. Routine and storm samples were analyzed for total phosphorus (TP), ortho phosphorus (orhto-p), total suspended solids (TSS), nitrate, and chloride. E. coli (bacteria) samples were also collected but only during bi-weekly grab sampling events. Field parameters including dissolved oxygen (DO), temperature, ph, and conductivity were also recorded during each bi-weekly site visit. This section provides one page summaries of three major water quality parameters of concern for the West Mississippi outfalls: TSS, TP, and E. coli. Both outfalls outlet to the Mississippi River which has a recently completed TMDL study for E. coli, a future TMDL study for TSS (in-progress), and a potential future TMDL study for TP based on proposed state river eutrophication standards. Monitoring results for the water quality parameters not covered in this section (ortho-p, nitrate and chloride) are summarized in Appendix A. Neither the Oxbow or 65 th Avenue outfalls have been assigned beneficial use classifications by the state of Minnesota. Both features have been extensively altered to function as underground stormwater conveyance systems and would most likely be considered Class 7 waters according to Minnesota Rules Chapter Class 7 waters are considered limited resource value waters that are not subject to state water quality standards as they are not protected for aquatic life and recreation due to lack of water, lack of habitat, or extensive physical alterations. As discussed previously, both outfalls discharge to the Mississippi River, which is classified as a class 2B water. Class 2B waters of the state are subject to certain pollutant water quality standards that are intended to protect aquatic life and recreation. For each water quality parameter discussed below, the class 2B standards are plotted to provide a general benchmark and give a sense of current water quality conditions of each site and how they may be affecting downstream resources. May

15 Sediment Insert WM_Sediment here Why We Monitor Sediment Total suspended sediment (TSS) is the amount of mineral (e.g. soil particles) and/or organic (e.g. algae) solids suspended in the water column. High concentrations of TSS cause turbid conditions which can lead to poor water clarity, decreased light penetration, and increased sedimentation and siltation. These conditions can lead to degraded habitat for fish and macroinvertebrates. TSS particles also provide sorption or attachment sites for other pollutants, such as metals and bacteria. Thus, high TSS can be used as indicators of other potential pollutants. State Standards and TMDLs The Oxbow and 65 th Ave storm sewer outfalls to the Mississippi River are considered class 7 waters and are not subject to the state water quality standards that govern class 2 waters (streams and rivers). The draft South Metro Mississippi River TSS TMDL includes general TSS allocations and will require 20 percent reductions in annual loading from the Upper Mississippi watershed. When this TMDL is adopted, the West Mississippi outfall monitoring data will be assessed against the TMDL requirements. Until then, the newly adopted 30 mg/l TSS standard for 2B streams will be used as a general benchmark. Watershed Actions to Address Sediment Numerous Best Management Practices such as ponds, infiltration basins, and rain gardens have been constructed in the watershed to capture and filter sediment from runoff. Cities have also increased street sweeping to capture particles and organic material. Sampling Results and Data Trends Oxbow outfall TSS concentrations are high during the high and very high flow conditions. All of the elevated samples were collected during, or shortly after rainfall storm events using automated sampling equipment. TSS concentrations for the Oxbow outfall were low and at or near detection limit (<5 mg/l) during the mid, low and very low flow conditions. TSS at the 65 th Ave outfall is similar to the patterns noted for Oxbow. Elevated TSS was observed only during large storm events and very high flow conditions. TSS was at or below detection limit (<5 mg/l) during the high, mid, low and very low flow conditions. These outfalls have only been sampled for a few years so it is difficult to determine longterm trends. At the 65 th Ave outfall, TSS has decreased both years (2011 and 2014) since the first year of monitoring in Similarly, average TSS decreased at the Oxbow outfall between 2013 and Several more years of TSS monitoring will need to be conducted to determine if these outfalls are exhibiting any real water quality trends.

16 Phosphorus Why We Monitor Phosphorus Phosphorus is an essential nutrient for all life forms and occurs naturally in soils and aquatic systems. High concentrations of phosphorus in streams can lead to algal blooms which decreases water clarity, and also depletes DO needed by aquatic organisms. Phosphorus in streams is typically measured in two ways, orthophosphate (ortho-p) and total phosphorus (TP). Ortho-P is the chemically active dissolved form of phosphate that algae and plants can directly consume. TP includes both ortho-p and particulate phosphorus (from plant and animal fragments and phosphorus attached to soil particles and suspended sediment). In 2005 the State of Minnesota banned the general use of phosphorus in fertilizers used on lawns and turf, allowing it only where soil tests indicate a need. State Standards and TMDLs The Oxbow and 65 th Ave storm sewer outfalls to the Mississippi River are considered class 7 waters and are not subject to the state water quality standards that govern class 2 waters (streams and rivers). The Mississippi River flows to Lake Pepin which is impaired for TP. The Lake Pepin Nutrient TMDL is in progress and will develop TP allocations and reduction targets for the Mississippi River watershed. At that time the outfall monitoring data can be assessed against the requirements set forth in this TMDL. Until then, the proposed 100 µg/l TP standard for 2B streams will be used as a general benchmark. Watershed Actions to Address Phosphorus Numerous Best Management Practices such as ponds, infiltration basins, and rain gardens have been constructed in the watershed to capture and filter phosphorus from runoff. Cities have also increased street sweeping to capture particles and organic material. Sampling Results and Data Trends Oxbow outfall TP concentrations are elevated during high and very high flow conditions. All of the elevated samples were collected during or shortly after rainfall storm events, where the phosphorus from sediment and organic material is easily washed off into storm sewers. TP concentrations for the Oxbow outfall were below 100 µg/l during the mid, low and very low flow conditions. TP at the 65 th Ave outfall occasionally exceeds 100 µg/l across most flow regimes. The highest TP levels were associated with rainfall events during very high flow conditions. However, high levels were also noted during mid and low flow conditions. These outfalls have only been sampled for a few years so it is difficult to determine longterm trends. However, summer average TP concentrations since 2010 (figure below) have remained relatively consistent at both outfalls.

17 E. coli Why We Monitor E. coli Bacteria such as E. coli in surface water can originate from the intestinal tracts of both humans and other warm-blooded animals, such as pets, livestock and wildlife. In sanitary-sewered urban watersheds, the primary source of E. coli and other fecal indicator bacteria are typically pets, birds and wildlife. When bacteria levels in surface waters are above health standards, humans exposed to the water may become sick and experience severe health problems. State Standards and TMDLs The Oxbow and 65 th Ave storm sewer outfalls into the Mississippi River are considered class 7 waters and are not subject to the state water quality standards that govern class 2 waters (streams and rivers). The Upper Mississippi River is impaired for bacteria. The Upper Mississippi River Bacteria TMDL Study and Protection Plan was completed in November The West Mississippi watershed was designated a Protection watershed with no assigned load reductions. Watershed Actions to Address E. coli Urban bacteria sources are widely diffuse. Best Management Practices such as ponds, infiltration basins, and rain gardens in the watershed can capture and filter E. coli. In addition, cities have and enforce pet waste cleanup ordinances, and undertake Canada goose management programs. Sampling Results and Data Trends Oxbow outfall E. coli concentrations are consistently low during all flow conditions and never exceed class 2B standards. E. coli at the 65th Ave outfall is typically high and often exceeds the class 2B standard during all flow conditions. These outfalls have only been sampled for a few years so it is difficult to determine long-term trends. The 65 th Ave outfall exhibited slightly lower E. coli levels in 2014 compared to sampling conducted in E. coli levels at the Oxbow outfall were very similar in 2013 and E. coli standards for class 2B waters state a 30 day geometric mean is not to exceed 126 cfu/100 ml (chronic standard) and 10% of values are not to exceed 1,260 cfu/100 ml (acute standard). The class 2B E. coli standards do not apply to these outfall sites but can be used as a general benchmark to describe and assess current TSS conditions for the West Mississippi outfall sites.

18 2.5 SUMMARY AND RECOMMENDATIONS Results of the 2014 flow and water monitoring for the Oxbow and 65 th Ave outfalls support the following conclusions and recommendations: 2014 was an above average year for precipitation and runoff throughout the West Mississippi watershed. The above average precipitation and rainfall in 2014 was driven by a few large storm events in April and June. Rainfall was at or below average for all other months in Flow data collected at the Oxbow site in 2014 indicate this outfall is extremely flashy and responds quickly to rainfall events. The large, intense rainfall events in April and June dislodged the monitoring equipment on several occasions making it difficult to monitor flow early in Additionally, high water levels in the Mississippi River made it impossible to monitor continuous flow at the 65 th Ave outfall in Wenck staff has now installed new mounting brackets in both the Oxbow and 65 th Ave outfall storm sewer pipes which should allow for more reliable flow monitoring in Both the Oxbow and 65 th Ave outfalls have continuous, year around baseflow and never go dry or stop flowing. Due to the flashiness of these sites, high TSS concentrations at the Oxbow and 65 th Ave outfalls have only been observed during first flush events using automated sampling equipment. TSS levels fall quickly to below detection limit (<5 mg/l) within a few hours of storm event. TSS does not seem to be a major concern at these outfalls. High TP concentrations at both outfalls sites are typically associated with higher flow events and therefore follow a similar pattern to TSS. Dissolved phosphorus (ortho-p) at both station is relatively low, suggesting most of the phosphorus is in particulate form and likely attached to TSS particles. The Oxbow outfall displays very low levels of E. coli and does not appear to be a source of bacteria to the Mississippi River. The 65 th Ave outfall, on the other hand, displayed very high levels of E. coli during all flow conditions. The catchment system for this outfall contains underground storage and is completely below grade so it is unclear if the source of bacteria is from the watershed/stormwater ponds, or if bacteria is colonizing and proliferating within the catchment system itself. It is recommended that a more thorough source assessment and longitudinal monitoring be conducted upstream of this watershed s outfall. May

19 3.0 Shingle Creek Stream Monitoring 3.1 OVERVIEW Continuous flow monitoring and water quality data was collected at two long-term stations (SC-0 and SC-3) and one newer station in Bass Creek (BCP) in 2014 (Figure 1-1). Station SC-0, also referred to as the outlet site or Webber Park monitoring site, is located upstream of the 45 th Avenue crossing in Minneapolis. The SC-3 monitoring station is located on the downstream end of where Shingle Creek crosses Brooklyn Boulevard in Brooklyn Park. The BCP monitoring site is located near the outlet of Bass Creek in Bass Creek Park in Brooklyn Park. SC-0 collects drainage from about 41 square miles, or approximately 93% of the watershed. The drainage area for SC-3 covers about 21 square miles which is approximately 47% of the Shingle Creek watershed. The BCP drainage area covers 8 square miles, or about 18% of the Shingle Creek Watershed. Additionally, there is one long-term USGS monitoring station on Shingle Creek at Queen Avenue near the border of Minneapolis and Brooklyn Center. This site is located upstream of SC-0 and drains approximately 31 square miles (70% of the watershed). The Shingle Creek WMC and USGS collected continuous flow and storm event samples at this location from 1996 through The USGS has monitored continuous flow at this site since 2001 and continuous conductivity since Real-time data is available through the USGS website ( 3.2 PRECIPITATION Table 3.1 summarizes monthly precipitation data for the New Hope National Weather Service located in the Shingle Creek watershed (Figure 1-1). Precipitation was well above average in April and June, and was close to average or below average during all other months. Overall, precipitation was 2.89 inches above normal in 2014, which was largely driven by a few large rainfall events in April and June. Table precipitation measured at the New Hope weather station. Month 2014 Precipitation (inches) Monthly Average Precipitation (inches) Departure from Long-Term Average (inches) January February March April May June July August September October November December TOTAL May

20 3.3 HYDROLOGY Stream stage (water level) was continually recorded from April 8 through November 13 at the BCP, SC-0, and SC-3 monitoring stations. Stage was converted to flow using sitespecific stage-discharge relationships (Appendix B). Flows outside the monitored period at each station were estimated using regression relationships with the USGS monitoring station, which operates and records flow measurements year around (Appendix B). Figure 3-1 presents the daily rainfall data along with average daily flow data for SC-0, SC-3, BCP, and the USGS monitoring station. Figure 3-2 presents daily rainfall and cumulative flow volume for all four Shingle Creek monitoring stations. As shown in Table 3.1, approximately 44% of the rainfall in 2014 fell during the months of April and June. Streamflow response was similar as about 36% of the total 2014 flow volume at the SC-0 station was recorded during April and June. Figure Average daily flow for each Shingle Creek monitoring station May

21 Figure Cumulative flow volume for each Shingle Creek monitoring station Annual flow volumes in acre-feet and runoff depth in inches for 2014 and the previous fourteen years are presented in Table 3.2 and Figure 3-3. The runoff depths for each flow monitoring station were calculated by dividing annual flow volume by the total area (acres) that drains to each station. Results indicate runoff depths for each monitoring station are quite variable and driven by the annual precipitation for that year, as well as precipitation in the preceding 1-2 years. For example, 2010 experienced above average rainfall (approximately 5.5 inches above normal), however runoff at all three monitoring stations were well below normal. Drought conditions and below average precipitation in both 2008 and 2009 likely resulted in increased storage throughout watershed which led to the low runoff observed in In general, runoff depth decreases from upstream to downstream (BCP to SC-0) throughout the Shingle Creek watershed. Bass Creek (BCP) has exhibited the highest runoff depth of all the Shingle Creek stations since monitoring began in Bass Creek and the upper portions of the watershed tend to have more areas with tighter soils than the lower watershed. May

22 Table 3-2. Shingle Creek annual flow volumes and runoff depths. BCP SC-3 5,210 acres 13,546 acres USGS 20,091 acres SC-0 26,618 acres Year Precipitation (in) Runoff (acre-ft) Runoff (in) Runoff (acre-ft) Runoff (in) Runoff (acre-ft) Runoff (in) Runoff (acre-ft) Runoff (in) , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Average , , , , Notes: Flow gaps for BCP, SC-3, and SC-0 were filled using discharge regressions with the USGS station values labeled SC-3 are from site SC precip data from the NWS in Chanhassen, data from the NWS in New Hope. May

23 Figure 3-3. Annual precipitation and runoff depth for all Shingle Creek monitoring stations. May

24 3.4 WATER QUALITY Routine water quality sampling in Bass Creek and Shingle Creek consisted of bi-weekly grab samples at BCP, SC-3, and SC-0 from early April through October. In addition to routine water quality samples, at least four storm composite samples were collected at each monitoring station. Routine and storm samples at each site were analyzed for TSS, TP, ortho-p, TKN, nitrate, chloride. Field parameters including DO, temperature, ph, and conductivity were also recorded during each routine sample site visit. This section provides one page summaries of four major water quality parameters of concern for Bass Creek and Shingle Creek: TSS, TP, chloride and DO. The selected parameters either have completed TMDL studies (chloride and DO), or may be subject to future TMDL studies based on newly adopted or proposed state water quality standards (TSS and TP). One parameter not covered in this section, E. coli, has not been monitored in the Shingle Creek watershed since Historic E. coli monitoring in Shingle Creek indicate bacteria levels are high and consistently exceed state water quality standards. In November 2014 the MPCA completed the Upper Mississippi River Bacteria TMDL Study and Protection Plan which outlines bacteria allocations and reductions for Shingle Creek and other tributaries to the Upper Mississippi River. The Shingle Creek watershed is assigned a 69 percent reduction in E. coli loading to the Mississippi River. The MPCA will allocate wasteload reductions to each of the MS4s in the watershed. Monitoring results for the water quality parameters not covered in this section (ortho-p, TKN and nitrate) are summarized in Appendix C. Appendix C also provides a summary of annual pollutant loads for each parameter calculated using the Flux32 Load Estimate Software (Walker, 1999). Bass Creek and Shingle Creek are considered class 2B waters and are subject to certain pollutant water quality standards that are intended to protect aquatic life and recreation. Protection of aquatic life is defined as the maintenance of healthy, diverse, and successfully reproducing populations of aquatic organisms, including invertebrates as well as fish. For each water quality parameter discussed below, the current or proposed class 2B water quality standards are plotted in order to compare the historic data (pre-2014) and the data collected in 2014 to these standards and give a general sense of water quality conditions in Bass and Shingle Creeks. May

25 Sediment Why We Monitor Sediment Total suspended sediment (TSS) is the amount of mineral (e.g. soil particles) and/or organic (e.g. algae) solids suspended in the water column. High concentrations of TSS cause turbid conditions which can lead to poor water clarity decreased light penetration, and increased sedimentation and siltation. These conditions can lead to degraded habitat for fish and macroinvertebrates. TSS particles also provide sorption or attachment sites for other pollutants, such as metals and bacteria. Thus, high TSS can be used as an indication of other potential pollutants. State Standards and TMDLs In 2011, the MPCA published a technical support document for state-wide TSS standards for all Minnesota rivers and streams. The criteria used to develop the standards are regional in scope and based on a combination of both biotic sensitivity to TSS concentrations and reference and least impacted rivers/streams. The proposed TSS standards were approved by EPA in January For Shingle Creek, the newly adopted TSS standards will require a concentration limit of 30 mg/l that must not be exceeded more than 10% of the time from April through September over a multiyear data window. Watershed Actions to Address Sediment Numerous Best Management Practices such as ponds, infiltration basins, and rain gardens have been constructed in the watershed to capture and filter sediment from runoff. Cities have also increased street sweeping to capture particles and organic material. Streambank erosion can also contribute to TSS, and several bank stabilization projects have been completed on Shingle and Bass Creeks. Sampling Results and Data Trends Bass Creek TSS concentrations are low and below state standards during all flow conditions. There are several large lakes and flow-through wetlands upstream of the monitoring location, which likely settle out most of the larger sediment particles. Shingle Creek TSS concentrations are moderately high and occasionally exceed the 30 mg/l standard. TSS exceedances are most common during the very high and high flow conditions. In general these flow conditions are associated with rain events greater than 0.5 inches. Historic TSS trends (figure below) indicate average annual TSS concentrations vary year to year depending on precipitation and flow and the number of large storm events. Overall, there appears to be a downward trend since 2001; however concentrations still occasionally exceed state standards. For Bass Creek, only 4% of the TSS samples collected between April and September in 2013 and 2014 exceed the 30 mg/l TSS standard. For Shingle Creek, approximately 18% (SC-3) and 21% (SC-0) of the TSS samples collected between April and September in the last 10 years exceed the 30 mg/l TSS standard.

26 Phosphorus Why We Monitor Phosphorus Phosphorus is an essential nutrient for all life forms and occurs naturally in soils and aquatic systems. High concentrations of phosphorus in streams can lead to algal blooms which decreases water clarity, and also depletes DO needed by aquatic organisms. Phosphorus in streams is typically measured in two ways, orthophosphate (ortho-p) and total phosphorus (TP). Ortho-P is the chemically active dissolved form of phosphate that algae and plants can directly consume. TP includes both ortho-p and particulate phosphorus (from plant and animal fragments and phosphorus attached to soil particles and suspended sediment). In 2005 the State of Minnesota banned the general use of phosphorus in fertilizers used on lawns and turf, allowing it only where soil tests indicate a need. State Standards and TMDLs In 2013, the MPCA published a technical support document which proposes statewide standards for TP and other eutrophication criteria for all Minnesota rivers and streams. For Bass and Shingle Creeks, the proposed TP standard would require a summer (June-September) average TP concentration limit of 100 µg/l. This proposed standard has not yet been adopted and is currently in the public review process. Watershed Actions to Address Phosphorus Numerous Best Management Practices such as ponds, infiltration basins, and rain gardens have been constructed in the watershed to capture and filter phosphorus from runoff. Cities have also increased street sweeping to capture particles and organic material. Sampling Results and Data Trends Bass Creek TP concentrations are high and exceed proposed state standards during all flow conditions. In Bass Creek, most of the TP at lower flow conditions is comprised of ortho-phosphate. The Bass Creek monitoring station is located downstream of the Cherokee Wetland, which may be releasing high levels of ortho-phosphate from wetland sediment during summer low-flow conditions. Shingle Creek TP concentrations are relatively low and typically do not exceed the 100 µg/l proposed standard. TP is slightly higher at SC-3 compared to SC-0, which may be the result of upstream loading from Bass Creek. Historic TP trends (figure below) indicate summer average TP concentrations fluctuate year to year depending on site and flow condition. Sampling has only been conducted in Bass Creek for two years; however summer average TP concentrations were above the proposed standard both years. Shingle Creek summer TP is consistently low with no significant data trends since The monitoring data for Bass Creek suggest average summer TP concentration is 129 µg/l. For Shingle Creek, average summer TP concentrations for the past 10 years are 66 µg/l (SC-3) and 42 µg/l (SC-0).

27 Chloride Why We Monitor Chloride Chloride is one of the major anions found in saltwater and freshwater systems. Chloride originates from the dissolution of salts in water that are found in soils as well as human/industrial pollution. Elevated chloride levels in urban streams are an indicator of non-point source loading from salt piles or urban streets where road salt has been applied. High levels of chloride can harm aquatic organisms by interfering with their osmoregulatory capabilities. State Standards and TMDLs Minnesota chloride standards for Class 2B waters state two or more samples exceeding 230 mg/l (chronic standard) over a consecutive three year period indicate impairment. Additionally, one or more sample exceeding 860 mg/l (acute standard) over the most recent 3 year period would also be considered impaired. In 1998, Shingle Creek was designated as impaired for chloride. Bass Creek was designated as impaired in A TMDL and Implementation Plan were improved in The TMDL determined that the likeliest source of chloride to the creek was road salt and that a 71% load reduction across the watershed was necessary to meet the TMDL. Watershed Actions to Address Chloride Most of the road authorities in the watershed are now pre-wetting road salt as it is applied, a technology that can reduce application rates by 25% or more. They are also more closely tailoring application rates to pavement temperature and other implementing other practices to most efficiently use road salt. The Commission has sponsored workshops for private applicators to learn about new application practices to reduce the use of salt. Sampling Results and Data Trends Winter chloride sampling for Shingle indicate concentrations are high and consistently exceed the chronic standard at all three monitoring stations. Intensive winter chloride sampling on Bass Creek started during winter and no data is yet available. The 5-year TMDL review did note a downward trend in the rate of road salt application for some road authorities. However, historic chloride data recorded at the USGS station (figure below) do not show any significant trends in winter chloride concentrations since the TMDL was completed in Due to the annual and seasonal nature of chloride, it will likely take several more years of monitoring data before in-stream chloride trends are observed. In 2014 the Commission undertook a review of progress toward meeting the TMDL. Road salting operations can vary widely event to event and even city to city depending on temperature and precipitation. This leads to extreme variability in the data year to year and even day to day, complicating efforts to identify trends.

28 Dissolved Oxygen Why We Monitor DO Dissolved oxygen (DO) is required by aquatic organisms for survival. If DO drops below acceptable levels, fish and other aquatic organisms may be harmed or die. DO concentrations experience daily cycles in most river and stream systems with concentrations reaching daily maximums in late afternoon when photosynthesis by aquatic plants is at its highest. Minimum DO concentrations typically occur early in the morning around sunrise when respiration rates exceed photosynthesis and oxygen is being consumed by aquatic organisms faster than it is replaced. Stream DO is also affected by water column and/or sediment oxygen consumption that occurs through the breakdown of organic compounds or reduced chemical compounds. Critical conditions for stream DO usually occur during late summer when water temperatures are high and stream flows are low. State Standards and TMDLs The Minnesota standard for class 2B cool/warm water fisheries requires DO concentrations shall not fall below 5.0 mg/l as a daily minimum in order to support the aquatic life and recreation of the system. The MPCA now recognizes that measurements taken after 9:00 am do not represent daily minimums, and thus measurements greater than 5.0 mg/l DO later in the day are no longer considered to be indications that a stream is meeting state standards. In 1998, Shingle Creek and Bass Creek were designated as impaired for DO. A TMDL and Implementation Plan were improved in The TMDL determined that the likeliest source of low DO were headwater DO conditions (Northland Wetland and Palmer Lake) and sediment oxygen demand in the various flow-through wetlands and the overwidened channel itself. A 70-97% load reduction in sediment oxygen demand was required to meet the TMDL. Watershed Actions to Address DO Cities have stabilized over four miles of stream to incorporate stream aeration features such as riffles and rock vanes, and to narrow overwide channels to reduce sediment oxygen demand. Sampling Results and Data Trends Three longitudinal DO surveys were performed in 2014 by measuring DO at seventeen sequential Bass Creek and Shingle Creek monitoring sites (figure below). These surveys were conducted on 7/21, 8/13, and 9/6. All sites were visited before 9:00 am to ensure that daily minimum DO measurements were being recorded. Results of these surveys show the reaches between 63rd Ave and BCP (Cherokee Wetland), I- 694 to Brooklyn Boulevard (Northland Wetland) and the outlet of Palmer Lake to Bass Lake Road (I-694 wetland) exhibited DO concentrations below 2.5 mg/l, likely due to large wetland complexes in these reaches. These wetlands decrease stream velocity in an area with high organic matter content, which elevates water column oxygen consumption as organic matter breaks down.

29 Figure DO longitudinal survey results. May

30 3.5 SUMMARY AND RECOMMENDATIONS Results of the 2014 flow and water monitoring for Shingle and Bass Creek support the following conclusions and recommendations: 2014 was an above average year in terms of precipitation and runoff throughout the Shingle Creek watershed. The above average precipitation and rainfall in 2014 was driven by a few large storm events in April and June. Rainfall was at or below average for all other months in Flow and precipitation over the last 4-5 years in Shingle Creek appear to be trending toward large, intense early season storm and runoff events (April-June), followed by long periods of dry, low-flow conditions later in the year (July-October). The streambank stabilization actions in the Biotic and DO TMDL and increasing infiltration in proximity to the stream to augment baseflow will help mitigate the impacts of these changes. Sediment (TSS) is consistently low in Bass Creek during all flow conditions, likely due to settling in the Cherokee Wetland upstream of the Bass Creek monitoring station. For Shingle Creek, TSS is low and not a concern at SC-3 and SC-0 during base-flow conditions and non-storm events. Elevated levels of TSS at SC-3 and SC-0 are common following rainfall events greater than 0.5 inches during high and very high flow conditions. Increased infiltration and treatment in the watershed will help reduce inflow of sediment during storm events. Overall, average annual TSS appears to have decreased in Shingle Creek since 2001, however concentrations still occasionally exceed state standards. It is recommended that TSS sampling in Shingle Creek continue in order to verify these trends. Phosphorus (TP) is high in Bass Creek and consistently above the 100 µg/l proposed standard. Phosphorus is relatively low at SC-3 and SC-0 as summer average concentrations are well below the proposed standard. The high phosphorus levels in Bass Creek are likely the result of phosphorus release from sediments in the Cherokee wetland upstream of the Bass Creek monitoring site. Paired sampling (upstream and downstream) of the Cherokee Wetland should be considered in 2016 to determine if it is a source of phosphorus to Bass Creek. If it is, BMPs such as aerators and/or iron enhanced sand filters may need to be considered. A recent review of the Shingle Creek chloride TMDL found that most of the road authorities in the watershed are now pre-wetting road salt as it is applied, which can reduce application rates by 25% or more. However, historic chloride data recorded at all three Shingle Creek monitoring stations do not show any significant trends in stream chloride concentrations. Due to the annual and seasonal nature of chloride, it will likely take several years of monitoring before in-stream trends are observed. Three early morning longitudinal DO surveys were performed along Bass Creek and Shingle Creek in These surveys found DO to be a concern throughout much of the creek, particularly downstream of flow-through wetland systems. DO sags (decreases) were noted in the Cherokee Wetland, Northland Wetland, Palmer Lake, and the large wetland system downstream of Palmer Lake. The Section 319 grant to install artistic reaeration structures will address two of these locations. Additionally, channel alteration through these wetland systems and/or bypass may need to be considered in order to improve DO to meet water quality standards. May

31 4.0 Citizen Assisted Lake Monitoring Program 4.1 OVERVIEW There are 16 lakes in the Shingle Creek watershed, and none in West Mississippi. The Shingle Creek Watershed Management Commission has participated in the Metropolitan Council s Citizen Assisted Lake Monitoring Program (CAMP) since This program is also an NPDES Education and Public Outreach BMP. CAMP was initiated by the Met Council to supplement the water quality monitoring performed by Met Council staff and to increase knowledge of water quality of Metro area lakes. Volunteers in the program monitor the lakes every other week from mid-april to mid- October, approximately 14 sampling events. They measure surface water temperature, Secchi depth, and collect surface water samples that are analyzed by the Met Council for TP, TKN, and chlorophyll-a. The volunteers also judged the appearance of the lake, its odor, and its suitability for recreation. Seven lakes were monitored in 2014: Pomerleau, Meadow, Upper Twin, Middle Twin, Lower Twin, Crystal, and Success. CAMP data supplement the monitoring conducted by the Commission every five years. The larger lakes are monitored every other year, and Magda, Success, Pomerleau, Meadow, and Cedar island are monitored every three years. 4.2 WATER QUALITY STANDARDS Water quality in Minnesota lakes is often evaluated using three associated parameters: TP, chlorophyll-a, and Secchi depth. Total phosphorus is typically the limiting nutrient in Minnesota s lakes meaning that algal growth will increase with increases in phosphorus. However, there are cases where phosphorus is widely abundant and the lake becomes limited by nitrogen or light availability. Chlorophyll-a is the primary pigment in aquatic algae and has been shown to have a direct correlation with algal biomass. Since chlorophyll-a is a simple measurement, it is often used to evaluate algal abundance rather than expensive cell counts. Secchi depth is a physical measurement of water clarity, measured by lowering a black and white disk until it can no longer be seen from the surface. Higher Secchi depths indicate less light refracting particulates in the water column and better water quality. Conversely, high TP and chlorophyll-a concentrations point to poorer water quality and thus lower water clarity. Measurements of these three parameters are interrelated and can be combined into an index that describes water quality. The State of Minnesota has established water quality standards for lakes (Tables 4.1 and 4.2). Thirteen of the 16 lakes in Shingle Creek do not meet those standards, and have been listed by the State and the EPA as Impaired Waters. Table 4-1. State of Minnesota water quality standards. (North Central Hardwood Forest Ecoregion) Total Phosphorus (µ/l) Chlorophyll-a (µ/l) Secchi Depth (meters) Deep Shallow May

32 Table 4-2. Shingle Creek lakes by depth. Deep Shallow Eagle Ryan Bass Pike Crystal Twin Middle Cedar Island Success Pomerleau Twin Upper Schmidt Twin Lower Magda Meadow Note: Palmer and Curtis are considered by the MnDNR to be wetlands CAMP MONITORING RESULTS Table 3.4 shows the provisional data from the Metropolitan Council for the seven lakes monitored by volunteers in Two of the lakes met the shallow lake standard in 2014: Lower Twin and Success. Lower Twin is delisted on the (d) list of Impaired Waters, meaning it is no longer considered impaired, and Success Lake is not on the list of Impaired Waters. It should be noted that while it meets state standards, water quality in Success Lake has declined over the last ten years or so. It appears that Success is receiving less groundwater inflow than in the past, which makes stormwater runoff a larger part of its overall annual water budget. Pomerleau is better than the state standard for chlorophyll-a and Secchi depth, but still shows elevated total phosphorus. Table CAMP summer average monitoring results. (Provisional data from Met Council; subject to change) Summer Average Lake Total Phosphorus (µ/l) Chlorophyll-a (µ/l) Secchi Depth (m) Crystal Middle Twin Pomerleau Deep Lake Standard Upper Twin Lower Twin Meadow Success Shallow Lake Standard Note: Cells that are in bold italics indicate where TMDL lake water quality goals are met. Figures 4.1 and 4.2 show the total phosphorus data for the shallow and deep lakes monitored in Upper Twin and Meadow Lakes experience wide fluctuations in water quality over the summer season (June to September) compared to the deep lakes. Refer to Appendix D for more detail and for lake trend data. May

33 Figure shallow lake CAMP total phosphorus data. Figure deep lake CAMP total phosphorus data. May

34 5.0 5-Year TMDL Review Lake Monitoring 5.1 OVERVIEW Schmidt and Bass Lakes were placed on Minnesota s 303(d) list of impaired waters for nutrients (total phosphorus) in A Total Maximum Daily Load (TMDL) study and Implementation Plan for both lakes were completed and approved in The Implementation Plans for these lakes recommended future monitoring activities to assess progress toward achieving the TMDL and state water quality standards. Those activities were incorporated into the Shingle Creek Watershed Management Commission s Third Generation Watershed Management Plan , including periodic intensive water quality monitoring, aquatic vegetation surveys, and fish sampling coordinated with the Department of Natural Resources (DNR). This section details the results of intensive water quality sampling and vegetation surveys conducted in 2014 on Schmidt and Bass Lakes in anticipation of the five year review of TMDL progress (including Pomerleau Lake) which will be completed later in 2015, or early LAKE DESCRIPTION Schmidt Lake is a small, shallow lake located in the City of Plymouth (Figure 1-1). Schmidt Lake has an approximate surface area of 37 acres, with a maximum depth of 27 feet and an average depth of 6 feet. The lake has a 34 acre littoral area that covers approximately 92% of the lake. Schmidt Lake receives direct runoff from a developed 232 acre watershed in the City of Plymouth. The watershed is predominantly single family residential. Schmidt Lake outlets through the City of Plymouth storm sewer system to Bass Lake. Bass Lake is a moderate sized shallow lake located in the City of Plymouth. Bass Lake has an approximate surface area of 175 acres, with a maximum depth of 31 feet and an average depth of 10 feet. Bass Lake has a 143 acre littoral area that covers approximately 82% of the lake. The Bass Lake watershed covers approximately 3,183 acres, which includes outflow from Pomerleau, Curtis and Schmidt Lakes, as well as inflow from Bass Creek and 7 storm sewer outfalls. The watershed is predominantly single family residential in the City of Plymouth, and a small portion in Maple Grove. Bass Lake outlets to Bass Creek on the eastern shore of the lake. 5.3 WATER QUALITY MONITORING Water quality sampling was conducted by Wenck staff at the long-term Schmidt and Bass Lake monitoring sites in Water depth at the Schmidt Lake monitoring site is approximately 20 feet deep and near the basin s deep hole. Water depth at the Bass Lake monitoring site is approximately 25 feet and also near the lake s deep hole. For both lakes, surface samples were collected bi-weekly from late May to early October and analyzed for TP, Secchi depth and chlorophyll-a Schmidt Lake Water Quality 2014 summer TP concentrations initially met the 60 µg/l standard until late August when concentrations increased above the standard for the last two sampling visits (Figure 5-1). Chlorophyll-a concentrations initially met the shallow lake standard (20 µg/l) through early May

35 July. Chlorophyll-a concentrations peaked in mid-july, and stayed above the standard through August with the exception of one measurement in late July. Secchi depth in general follows the same trend as chlorophyll-a. Secchi depths began the season meeting shallow lake standards, but decreased throughout most of the summer growing season. Historic data suggest TP, chlorophyll-a and Secchi depth all showed improving trends from 1998 to 2011 (Figure 5-2). However, all three parameters began to increase in 2012 and water quality has degraded each year since Bass Lake Water Quality Summer TP concentrations in 2014 exceeded the 60 µg/l standard for shallow lakes on all of the site visits after July 1 st (Figure 5-3). TP concentrations were below the shallow lake standard in June and steadily increased throughout the season. Chlorophyll-a concentrations also exceeded the shallow lake standard beginning in early July. Chlorophyll-a measurements peaked in mid-august at 82 µg/l and remained high for the remainder of the season. Initial Secchi depth measurements met the shallow lake water quality standards; however, water clarity followed the same trend as chlorophyll-a. The steady increase of TP and chlorophyll-a concentrations throughout the growing season in the surface and deep water suggest that internal loading may be an important nutrient source in Bass Lake. Historic data suggests Bass Lake has high TP concentrations that regularly exceed the shallow lake water quality standards (Figure 5-4) with no obvious increasing or decreasing trends in the last 10 years. Similar to TP, average annual chlorophyll-a and Secchi depth measurements have exceeded deep lake standards each year. May

36 Figure 5-1. Schmidt Lake 2014 TP, Chlorophyll-a and Secchi depth. May

37 Figure 5-2. Schmidt Lake historic TP, chlorophyll-a and Secchi Depth May

38 Figure 5-3. Bass Lake 2014 TP, Chlorophyll-a and Secchi depth. May

39 Figure 5-4. Bass Lake historic TP, chlorophyll-a and Secchi Depth May

40 5.4 VEGETATION SURVEYS Point-intercept surveys using methodology developed by the Minnesota Department of Natural Resources (DNR) were conducted on June 24, 2014 and August 21, 2014 on Schmidt and Bass Lakes. Point-intercept sample points were established in GIS across the entire lake basin using a 50 meter grid file. A total of 72 points and 131 points were sampled during each Schmidt and Bass Lake survey, respectively. The surveyed grid was downloaded onto a GPS unit that was used to navigate to each sample point during the survey. One side of the boat was designated as the sampling area. Water depth was recorded at each sample point in increments estimated to the nearest tenth of a foot using a survey range pole and electronic depth finder. Wenck staff identified all plant species found within a one meter squared sample site at each survey point. A weighted sampling hook attached to a rope was used to survey vegetation not visible from the surface. All vegetation species observed were identified to the species level where possible. Species abundance rankings were also visually assessed and recorded at each monitoring point using a 0-5 ranking scale (0 = no plants; 5 = heavy plant abundance). Water clarity was also recorded during each survey by measuring the depth at which a Secchi disk was visible when lowered into the water. The late summer surveys were conducted to assess each lake s overall native plant community and diversity during the heart of the summer growing season. The early summer surveys were conducted to estimate the distribution and abundance of curly-leaf pondweed. Curly-leaf pondweed is a non-native plant species that can out-compete native plant species and disrupt lake ecosystems by changing the dynamics of internal phosphorus loading. Curly-leaf pondweed is a perennial, submersed aquatic plant that was first noted in Minnesota around Curly-leaf pondweed has the ability to grow slowly throughout the winter, even under thick ice and snow cover. Thus, by the time other species start growing in the spring, curly-leaf plants are large enough to block light penetration to the bottom. By late spring, curly-leaf pondweed can form dense surface mats which interfere with recreation activities. By mid-summer, these dense mats senesce and die back, releasing nutrients that can contribute to undesirable algae blooms. Before curly-leaf pondweed plants die back, they form hardened stem tips called turions, which serve the function of vegetative reproduction. These turions sprout in the fall and begin the plant s cycle again Schmidt Lake Survey Results Frequency of occurrence of each plant species observed in Schmidt Lake is summarized in Table 5-1. Vegetation was found at 61 of 72 (85%) sampling sites during the June 24, 2014 survey. In areas of the lake less than 15 feet deep, vegetation was found at 61 of 64 (95%) sites. Eight species of aquatic vegetation were documented at sample stations during this survey. The maximum depth at which vegetation was found during this survey was 12.5 feet. In general, vegetation occurrence and diversity decreased with depth, and most points shallower than 15 feet were vegetated. Secchi depth was measured at 2.4 meters (8.0 feet) during the survey. Figure 5-5 shows the relative plant biovolume in Schmidt Lake during each survey. Vegetation was found at 60 of 72 (83%) sampling sites during the August 21, 2014 survey (Figure 11). In areas of the lake less than 15 feet deep, vegetation was found at 60 of 65 (92%) sites. Nine species of aquatic vegetation were documented at sample stations during the August 21, 2014 survey. The maximum depth at which vegetation was found was 12 feet, with frequency of occurrence and diversity decreasing with depth. Secchi depth was measured at 0.9 meters (2.8 feet) during this survey. May

41 The most common species observed during the June 2014 survey were coontail (74%) and Canada waterweed (40%). Curly-leaf pondweed was observed at 11 sampling stations (15%) during the June survey. The species commonly observed during the August survey included coontail (76%), wild celery (60%) and bushy pondweed (32%). As expected, curlyleaf pondweed was not present at any of the survey locations during the August survey. Eurasian milfoil, another non-native invasive species, was observed at 13 stations (18%) during the June survey, and only one stations (1%) during the August survey. Table 5-1. Plant species frequency of occurrence in Schmidt Lake. Common Name Scientific Name Coontail is a native plant species to Minnesota lakes and wetlands. Coontail, along with the native pondweed species, have more typical life cycles compared to curly-leaf pondweed. They typically begin growing in late spring and peak during the warm summer months before gradually dying back when water temperatures decrease in the fall. As a result, these species are not considered a source of nutrients or a water quality concern during the summer growing season. In fact, these species can be beneficial to water quality through nutrient uptake and stabilizing bottom sediments from re-suspension by wind and rough fish. Coontail thrives in nutrient rich environments and can reproduce rapidly to form thick stands of tangled stems and vegetation mats at or below the water s surface. In shallow areas, these vegetative mats can interfere with water recreation such as boating, fishing, and swimming. In high abundance, coontail can crowd out less-aggressive native species which can lead to lower species diversity. May Percent Occurrence June 24, August 21, Bushy Pondweed 11% 32% Canada waterweed Elodea canadensis 40% 17% Chara -- 1% Coontail Ceratophyllum demersum 74% 76% Curly-leaf pondweed Potamogeton crispus 15% -- Eurasian watermilfoil Myriophyllum spicatum 18% 1% Flat-stem pondweed Potamogeton zosteriformis -- 1% Narrow-leaf pondweed group 18% -- Sago pondweed -- 3% White waterlily Nymphaea ordorata 11% 17% Wild celery Vallisneria americana 28% 60% Curly-leaf pondweed was fund at 15% of the sampling stations during the June 2014 survey. The species was most abundant throughout the shallow western arm of the lake and along the central and southern shoreline of the main part of the lake (Figure X). It should be pointed out that there were no dense mats of curly-leaf pondweed observed during the June 2014 survey as curly-leaf pondweed abundance rankings never exceeded 3 at any of the survey points. In several lakes throughout the Metro Area, curly-leaf pondweed has been observed at over 50% of sample points early in the year. In these lakes, curly-leaf pondweed is the dominant plant species during the early growing season and out-competes and suppresses development of native plant species. At this time, curly-leaf pondweed is relatively under control in Schmidt Lake and does not appear to be affecting growth of other vegetation in the lake. Eurasian watermilfoil, was also relatively low in Schmidt Lake and does not appear to be a major concern or nuisance at this time (Figure 5-6).

42 Coontail was the dominant plant species during both the June (74%) and August (76%) surveys. Abundance rankings for coontail were high and consistently exceeded 2 throughout much of the lakes littoral area during both surveys. In many places, coontail formed dense floating and submerged mats which made navigating through these portions of the lake extremely difficult. While coontail does not pose a threat to water quality in Schmidt Lake, it is a nuisance and does interfere with recreation in certain areas of the lake Bass Lake Survey Results Frequency of occurrence of each plant species observed in Bass Lake during each survey is summarized in Table 5-2. Vegetation was found at 31 of 131 (24%) sampling sites during the June 24, 2014 survey. In areas of the lake less than 15 feet deep, vegetation was found at 31 of 104 (30%) sites. Eight species of aquatic vegetation were documented at sample stations during this survey. The maximum depth at which vegetation was found during this survey was 11 feet. In general, vegetation was most dense in and near the lagoon on the southwest corner of the lake. Secchi depth was measured at 1.4 meters (4.5 feet) during the survey. Vegetation was found at 24 of 131 (18%) sampling sites during the August 21, 2014 survey. In areas of the lake less than 15 feet deep, vegetation was found at 24 of 109 (22%) sites. Nine species of aquatic vegetation were documented at sample stations during the August 21, 2014 survey. The maximum depth at which vegetation was found was 7 feet, with frequency of occurrence and diversity decreasing with depth. Secchi depth was measured at 0.6 meters (2.0 feet) during this survey. Figure 5-7 shows the relative plant biovolume in Bass Lake during each survey. The most common species observed during the June 2014 survey were coontail (22%) and curly-leaf pondweed (21%). Coontail (20%) was the most common species observed during the August survey. As expected, curly-leaf pondweed was not present at any of the survey locations during the August survey. Eurasian milfoil, another non-native invasive species, was not observed during either survey. Table 5-2. Plant species frequency of occurrence in Bass Lake. Common Name Scientific Name Percent Occurrence June 24, 2014 August 21, 2014 Bushy Pondweed -- 2% Chara 1% 2% Coontail Ceratophyllum demersum 22% 20% Curly-leaf pondweed Potamogeton crispus 21% -- Potamogeton Flat-stem pondweed zosteriformis 2% 2% Leafy pondweed Potamogeton foliosus -- 1% Narrow-leaf pondweed group 5% -- White waterlily Nymphaea ordorata 2% 8% Wild celery Vallisneria americana 3% 9% Yellow waterlily Nuphar variegatum 8% 8% May

43 Curly-leaf pondweed was most abundant in the southwestern portion of the lake, while other portions of the lake were limited to a few small strands (Figure 5-8). At this time, curly-leaf pondweed is moderately abundant in Bass Lake during the early summer growing season. Native species plant abundance decreased between the June and August survey indicating curly-leaf pondweed and other factors (algae growth, transparency, etc.) are likely affecting the growth of native vegetation in the lake. Coontail was the dominant plant species during both the June (22%) and August (20%) surveys. Abundance rankings for coontail ranged between 1-4, and were highest in the western and southwestern portions of the lake (Figure 5-7). In a couple places, coontail formed dense floating and submerged mats which made navigating through these portions of the lake difficult. While coontail does not pose a threat to water quality in Bass Lake, it is a potential nuisance species that may proliferate as water quality and water clarity within the lake improves. May

44 Figure 5-5. Schmidt Lake early summer (left) and late summer (right) plant biovolume. May

45 Figure 5-6. Eurasian milfoil and curly-leaf pondweed density in Schmidt Lake. May

46 Figure 5-7. Bass Lake early summer (left) and late summer (right) plant biovolume. May

47 Figure 5-8. Eurasian milfoil and curly-leaf pondweed density in Bass Lake May

48 6.0 Biological Monitoring 6.1 OVERVIEW 6.2 INTRODUCTION The Commission does not routinely undertake biological monitoring, but does obtain biological data by sponsoring volunteer monitoring through Hennepin County Environmental Services. High school students and their teachers monitor macroinvertebrates in streams through the River Watch program, and adult volunteers led by trained leaders monitor macroinvertebrates and vegetation in wetlands through the Wetland Health Evaluation Program (WHEP) 6.3 STREAM MACROINVERTEBRATE MONITORING Routine stream macroinvertebrate monitoring in both watersheds is conducted by volunteers through Hennepin County s River Watch program. This program was initiated in 1995 to provide hands-on environmental education for high school and college students, promote river stewardship, and obtain water quality information on the streams in Hennepin County. It is a program of the River Network, a national non-profit organization that promotes community-based programs to restore and protect rivers and watersheds. Through the River Watch program, over 550,000 volunteers nationwide assist in watershed monitoring and assessment. Hennepin County coordinates student and adult volunteers who use the River Watch protocols to collect physical, chemical, and biological data to help determine the health of streams in the watershed. One of the Commissions goals is to track changes in streams. Examining the macroinvertebrate community provides a picture of the health of the stream. The results are qualitative and should be interpreted as one indicator of the rivers health, not scientifically precise data. Another goal is to promote an understanding of the watershed and how water quality is related to land use. The water quality found in one short stretch of stream does not just reflect what is happening in one area. It reflects the water quality of all upstream areas draining into it. The program began on Shingle Creek in spring 1996 and on Mattson Brook in West Mississippi in spring Two Shingle Creek sites have been monitored relatively longterm. Mattson Brook was in the past regularly monitored, and after a gap a new volunteer group was found and the monitoring record resumed. Some other sites on Shingle Creek have been monitored for a few years and then for one reason or another dropped from the program. Retention of volunteer groups is an ongoing issue for this program. Changes in the high school graduation standards, key teaching staff retirements, and school budget reductions all make it difficult to attract and retain school groups. May

49 6.4 FINDINGS Monitoring In 2014, across the county 19 stream stretches were monitored in the spring and/or fall. Overall, five sites received a B grade; eleven sites a C grade; and three sites a D grade. The SCWM sponsored monitoring at two sites in Shingle Creek in 2014 and one on Mattson Brook in West Mississippi. The grading below shows annual variability that is likely related to precipitation and wet/dry periods. The site adjacent to Park Center High school has one of the longest data records of any of the RiverWatch sites in Hennepin County. The second-longest site is at Webber Park, near the SC-0 monitoring station. That site has in the past been monitored by Patrick Henry High School, but the teacher spearheading that effort was reassigned to another high school and they have not participated in Table 6-1. Park Center High School Site #10. Monitored by Park Center High School. Year Grade Year Grade 2014 D D 2013 D D C C 2011 C D 2010 C 2000 D C D C D C C C 1996 B C Table 6-2. Lions Park, Brooklyn Center. Monitored by Calvin Christian High School. Year Grade Year Grade 2014 D None 2013 C 2010 None 2012 B C+ Table 6-3. Mattson Brook Site #20. Monitored by Minneapolis South High School. Year Grade Year Grade 2014 C 2004 C 2013 None* 2003 C 2012 C C 2010 C 2000 C 2009 C 1999 B 2008 C B 2007 C- *Water levels too low Sites monitored in previous years but not in 2014: May

50 Table 6-4. Webber Park - Site #28. Monitored by Patrick Henry High School. Year Grade Year Grade 2012 D C 2011 D C C 2002 C C C 2008 C Table 6-5. North Hennepin Community College Site #8. Monitored by Metro Tech Academy. Year Grade Year Grade 2013 D D C Table 6-6. Boone Avenue - Site #27 Year Grade Year Grade 2010 C 2007 C Not monitored 2002 D C D Table 6-7. Brookdale Library. Year Grade Year Grade 2009 C Discussion Based on the limited River Watch sampling, organisms found indicate average to impaired conditions for impacted urban streams. Variability is likely due to the amount of sustained flow in the streams. 6.5 WETLAND MONITORING Three sites in the Shingle Creek watershed and two sites in the West Mississippi watershed were monitored through the Hennepin County Environmental Services Wetland Health Evaluation Program (WHEP). The WHEP program uses trained adult volunteers to monitor and assess wetland plant and animal communities in order to score monitored wetlands on an Index of Biological Integrity for macroinvertebrates and for vegetation. In 2014 volunteers assessed 36 sites across Hennepin County. The macroinvertebrate IBI scores ranged from a low of 6 (poor) to a high of 27 (excellent), with most of the sites in the (moderate) range. The vegetation IBI scores ranged from 11 (poor) to 27 (excellent). This is unsurprising as most urban wetlands exhibit variable vegetative diversity due to their altered hydrology and pollutant and sediment conveyed by storm sewers. One site monitored in Brookdale Park in Brooklyn Park scored a 24 (excellent) on macroinvertebrates but 15 (poor) on vegetation diversity, illustrating the difficulty of rating wetlands. May

51 Monitoring Five sites were monitored in 2013: one in West Mississippi (Brooklyn Park) and four in Shingle Creek (Brooklyn Center, two in Brooklyn Park, and Wetland 639W in Crystal.) The West Mississippi site is in Brooklyn Park and has been monitored since The site is in a series of ponds and remnant wetlands north of Oxbow Lake near Regent and 101 st Avenues North related to the 2002 development of Oxbow Commons. This area has rapidly developed in the past ten years, contains protected and mitigation wetlands, and is in an area where other wetlands have lost their hydrology. This site scored moderately well on both metrics (Table 6-8). Table 6-8. Wetland monitoring site BP-4 Oxboro Ponds. Year Invertebrate 16 (moderate) 16 (moderate) 24 (excellent) Vegetation 16 (moderate) 21 (moderate) 21 (moderate) Figure 6-1. Wetland monitoring site BP-4 at Oxboro Ponds in Brooklyn Park. One site was monitored in Brooklyn Center near Palmer Lake. Site BC-2 (Figure 6-2) is a stormwater pond constructed in an upland part of the Palmer Lake Basin. This pond receives runoff from a large neighborhood to the west that had previously flowed untreated in the basin (Table 6-9.) Table 6-9. Wetland monitoring site BC-2. Year Invertebrate 14 (poor) 14 (poor) 16 (moderate) Vegetation 17 (moderate) 19 (moderate) 19 (moderate) May

52 Figure 6-2. Wetland monitoring site BC-2 in Palmer Lake Park, Brooklyn Center. The second Shingle Creek site monitored was Wetland 639W in Crystal. This site showed moderate invertebrate and vegetative diversity (Table 6-10). Table Wetland monitoring site CR-1. Year Invertebrate 16 (moderate) 16 (moderate) 22 (moderate) Vegetation 13 (poor) 17 (moderate) 19 (moderate) Two new sites in Brooklyn Park were monitored in BP-5 is in Brookdale Park, in a series of wetlands just south of Shingle Creek, downstream of Noble Avenue and monkey falls. Old records show that before the Creek was straightened and channelized through the park, it meandered through these wetlands. This site had the best invertebrate diversity, and moderate vegetative quality (Table 6-11 and Figure 6-3.) Table Wetland monitoring site BP-5. Year 2014 Invertebrate 24 (excellent) Vegetation 15 (moderate) Figure 6-3. Wetland monitoring site BP-5 in Brookdale Park, Brooklyn Park. The final site, BP-6, is in Greenhaven Park in Brooklyn Park (Figure 6-4). This site is where Shingle Creek, which is at that point flowing north, turns almost 90 degrees and flows under Bottineau Boulevard and past Wal-Mart. This site has not previously been monitored, and showed moderate vegetative and invertebrate diversity (Table 6-12). May

53 Table Wetland monitoring site BP-6. Year 2014 Invertebrate 22 (moderate) Vegetation 25 (moderate) Figure 6-4. Wetland monitoring site BP-6 in Greenhaven Park, Brooklyn Park. Wetlands previously monitored by not in 2014 include: A wetland in Brooklyn Park s Environmental Preserve was monitored for six years. This higher-quality wetland receives stormwater from a large area to the west. This recentlydeveloped area is served by a number of detention ponds to treat runoff, and the health of BP-1 is one indicator of the effectiveness of that treatment in protecting downstream resources. Table Wetland monitoring site BP-1. Year Invertebrate 28 (excellent) 22 (moderate) 21 (moderate) 20 (moderate) 20 (moderate) 18 (moderate) Vegetation 13 (poor) 19 (moderate) 22 (moderate) 19 (moderate) 19 (moderate) 21 (moderate) In 2008 and 2009 a wetland in Brooklyn Park s Jewel Park was monitored (Table 6-14). Typical of small remnant wetlands in the watershed, this site is dominated by cattails and this monoculture greatly reduces both invertebrate and plant diversity. This site was not monitored in 2010 or Table Wetland monitoring site BP-3. Year Invertebrate 10 (poor) 20 (moderate) Vegetation 7 (poor) 10 (poor) Another wetland in the Shingle Creek watershed in Brooklyn Park just north of Palmer Lake was monitored in The results (Table 6-15) illustrate how variable biotic health can be based on precipitation. May