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HomeMy WebLinkAbout07/31/2008 Env Bd Packet• • • City of Lino Lakes Environmental Board Meeting July 31, 2008 6:00 p.m. AGENDA 1. Call to Order 2. Approval of Minutes May 28, 2008 3. Approval of Agenda 4. Open Mike 5. Action Items A. Recommendation to participate with Rice Creek Watershed District and Reshanau Lake Association in Water Quality Efforts. 6. Discussion Items A. Recycling/Mike Larson of JR's Advanced Recyclers B. Blue Heron Days Parade 7. Adjourn • ENVIRONMENTAL BOARD MEETING MAY 28, 2008 CITY OF LINO LAKES MINUTES DATE : May 28, 2008 TIME STARTED : 6:32 P.M. TIME ENDED : 8:15 P.M. MEMBERS PRESENT : Mary Jo O'Dea, Barbara Bor, Peter Brown and Paula Andrzejewski MEMBERS ABSENT : Pam Hartley, Kimberly Brouillet and Martha DeHaven STAFF PRESENT : Environmental Coordinator Marty Asleson 1. CALL TO ORDER Ms. O'Dea called the meeting to order at 6:32 p.m. 2. APPROVAL OF MINUTES April 30, 2008 Page three, first paragraph change Mr. to Ms. • Mr. Brown made a motion to approve the April 30, 2008 minutes with change. Ms. Andrzejewski seconded the motion. Motion carried unanimously. 3. APPROVAL OF AGENDA Add additional items under Discussion Items: B. Blue Heron C. Solid Waste Recycling Ms. Andrzejewski made a motion to approve agenda. Mr. Brown seconded the motion to approve agenda. Motion carried unanimously 4. OPEN MIKE Open mike closed at 6:35 p.m. 5. ACTION ITEMS None. • 6. DISCUSSION ITEMS 1 DRAFT MINUTES ENVIRONMENTAL BOARD MEETING MAY 28, 2008 A. Resource Management Plan (RMP) and Rule Update /Jason Naber of FOR Mr. Asleson stated Mr. Jason Naber from Emmons & Oliver Resources, Inc. is working with the Rice Creek Watershed District (RCWD) on the Resource Management Plan (RMP). Mr. Naber will review the RMP and Rule Updates with the board. Mr. Naber stated he has been a consulting engineer with RCWD on the RMP. He stated this is a cooperative effort that began roughly a year and '/2 ago. He stated this is the first time he has coordinated so closely with a city. He stated the Lino Lakes planning efforts are an integration of the RMP (RCWD), Comprehensive Land Use Plan (City), TMDLs (RCWD) and Surface Water Management Plan & Municipal Stormwater Permitting (City), which will be fully integrated with Army Corps of Engineers 404 and allowing state permitting. Ms. Bor questioned the standards of best practices vs. what gives a vision to 2030. Mr. Naber stated the state process will require implementing or adopting a rule that implements this plan. An applicant that comes into the City of Lino Lakes will be under the rule that we are adopting. Those rules stay until it gets amended. He stated the RCWD requires permits for the stormwater portion of an application. The TMDL program is being administered by the Minnesota Pollution Control Agency (MPCA). WHAT ARE THE OUTCOMES? FUTURE CONDITIONS Understanding Consequences and Constraints Make Reasonable Predications DEFINED LOCAL PERMITTING PROCESS Stormwater Controls Wetlands Land Use & Ordinances DEFINED FEDERAL PERMITTING PROCESS Permit Review Guidance Document Advanced Identification (ADID) Special Area Management Plan (SAMP) General Permit 2 DRAFT MINUTES • ENVIRONMENTAL BOARD MEETING MAY 28, 2008 WHAT ARE BENEFITS? LAND OWNER Site Layout Flexibility Permitting Consistency & Efficiency Realistic Expectations WATERSHED DISTRICT Planned for Future Demonstrated Control Results Non - Degradation Meets No Net Loss CITY OF LINO LAKES Ecologically -based Controls Stormwater Infrastructure Properly Sized Parks and Open Space Coordination Mr. Naber continued to review the main points for getting involved in this project. He stated this is a watershed based concept of management. Ms. Bor stated that the coordination with other cities is critical. 1111 Mr. Naber viewed maps with the board. • Map 2 Showed the Preliminary Full Build under RCWD 2007 Rules. This map showed areas of capacity problems if the city is fully built out. Map 3 Showed Full Build Out with RMP & 2008 Rules. This map showed the wetland conservation corridor. He stated wetland areas are a priority and they protect and preserve. Mr. Naber stated that restoration projects can actually accommodate future development. Ms. O'Dea questioned who would be conducting the restoration. Mr. Naber stated the RCWD can put the restoration into a plan to become a capital improvement project. He stated there is potential of city funding and the RCWD can look at special assessment. Ms. O'Dea questioned how restoration on private properties would occur. Mr. Naber stated there would need to be cooperation from private land owners. Mr. Asleson stated that there would be monetary incentives. Ms. O'Dea stated in order to make this project successful, surrounding cities would need to be open to the plan. Mr. Naber stated surrounding cities have been invited to all the public meetings. He also stated surrounding cities need to be supportive for the approval of this project. 3 DRAFT MINUTES ENVIRONMENTAL BOARD MEETING MAY 28, 2008 Ms. Bor questioned if this plan would impact the lakes by 2030. Mr. Naber stated certain shifts of the plan can be noticeable in a matter of years Mr. Naber stated the Resource Management Units took a look from nutrient loading from a 1 year storm and a 100 year storm. A city that is fully developed does not want to lose wetland functions. HOW IT WORKS: RMP — Based Permitting Sequence — Developing Parcel RMP - will provide use of landscape level information. Wetland preservation corridor WCA — CWMP 404 -ADID Stormwater Management Areas — Capacity needs — TMDL Standards. Next stage — collection of site specific data - wetland delineation — functional assessment — soil borings — T & E Survey. Applying the Rule to define the actual WPC Boundary — RMP Rule Defined WPC Boundary and Delineated Wetland Boundaries. Ms. O'Dea questioned the concept of delineation. Mr. Naber stated this is done at a remote scale and basically is done by soil mapping and vegetation and then some ground checking. Hydrology requires years of monitoring in some cases. Ms. O'Dea stated the more that is accomplished to create the predevelopment meeting atmosphere the better. Mr. Naber continued his presentation: MEETING PERMITTING OBJECTIVES WETLANDS Minimize Impacts Buffers High Quality Avoidance MITIGATION Quality, Type, Function Replacement Location STORMWATER MANAGEMENT Rate and Volume Control 4 DRAFT MINUTES • • • • ENVIRONMENTAL BOARD MEETING MAY 28, 2008 TMDL Compliance WHAT ARE ENVIRONMENTAL BENEFITS Wetlands Lakes Streams Wildlife DEVELOPMENT BENEFITS Alternatives Analysis Permitting Consistency Site Layout Flexibility Ms. O'Dea questioned if the full build out was flexible. He stated a way to think about this is by doing one thing to offset another. How is the RMP Implemented? RCWD will adopt the Lino Lakes Resource Management Rule. RCWD will provide ongoing assistance to the City and developers by: Site Reviews Early Coordination of Municipal Projects Identification of Joint Projects RCWD Comprehensive Plan Update Project Feasibility Studies Implement Plan Capital Improvement Plan Mr. Brown questioned how wetland banking works. Mr. Naber stated there is an official process that needs to take place. There is an application process through the Board of Water and Soil Resources for the credits. Credits can be entered into a state wetland bank. He stated the State encourages local planning. B. Blue Heron Update Mr. Asleson stated he visited Peltier Island after the storms of Sunday, May 25, 2008. He stated the birds are fine and nests were not harmed. He stated there are approximately 45 — 46 nests occupied at this time. C. Solid Waste Update Mr. Asleson stated the goal for tonnage that the city is asked to meet by the county standpoint just barely made it in 2007. Mr. Asleson stated he would like suggestions from the board as to ways not to fall below its goal. 5 DRAFT MINUTES ENVIRONMENTAL BOARD MEETING MAY 28, 2008 Add to next agenda: Recycling Tonage Increase recycling tonnage. Mr. Asleson stated there has been a tonnage loss due to not having a second fall recycling day. Appliance recycling is free and truck set up is free for collection of appliances. 7. ADJOURN It was noted that the next meeting of the Environmental Board will be on June 25, 2008. There being no further business, Ms. Bor moved to adjourn at 8:15 p.m. Ms. Andrzejewski seconded the motion. Motion carried unanimously. Transcribed by: Lisa Hogstad Community Development Secretary 6 DRAFT MINUTES • • • • Agenda Item 5A Environmental Board Meeting Date: July 31, 2008 Topic: Reshenau Lake Management Cost Sharing Background: Reshanau Lake is a 336 acre artificially created lake. The lake existed as a wetland until the late 1960's and early 1970's. After this time the wetland was dredged and took on the function of a shallow lake. In recent years residents have experienced a decline in lake water quality. Efforts have been made in the past to initiate rehabilitation of the lake. Please see Attachment 1, Reshenau Lake Management Plan, (Curley -leaf Pondweed Management) dated 4/8/2005 for a more comprehensive history of lake property owners efforts, and memo from Mathew Kocian from the Rice Creek Watershed District. Matt will attend the meeting on July 31st, to discuss vegetation management and other lake management issues concerning Reshanau Lake. Request Most of the effort at this time is centered around Curley Leaf Pondweed management. See item VII of Attachment 1. Other management issues identified are rough fish management, native plant restoration and shoreline restoration. A projected budget for 2009 is around $40,000. If the City were to partner in the effort to dean up Reshanau Lake, our cost would be 1 /3rd of the $40,000 or approximately $13,000. City Staff are proposing to use Surface Water Management monies for this purpose. Recommendations 1. Recommend the City form a partnership with the Rice Creek Watershed District and the Lake owners of Reshanau Lake to manage Reshanau Lake for better water quality, and to use Surface Water Management dollars for the City match 2. Other recommendations as per the Lino Lakes Environmental Board. 1. Reshenau Lake Management Plan, (Curley -leaf Pondweed Management) 2. Memorandum from Mathew Kociam, RCWD, 7/1/2008 • RESHANUA LAKE MANAGEMENT PLAN (Curly -leaf Pondweed Management) 4/8/2005 RICE CREEK WATERSHED DISTRICT Reshanau Lake Management Plan February 8, 2005 RESHANAU LAKE MANAGEMENT PLAN Table of Contents I. Introduction Page 2 II. Problem Statement Page 2 III. Management Goals Page 2 IV. History /Summary of Existing Data Page 4 V. Situational Analysis Page 5 VI. Objective Page 6 VII. Budget and Timeframe Page 8 VIII. Organization Page 8 IX. Funding Page 9 X. Summary Page 9 List of Figures Figure 1 Drainage area for Reshanau Lake G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc l • Reshanau Lake Management Plan L Introduction During the summer of 2004, a number of residents, who own property on Reshanau Lake, observed that the submerged aquatic vegetation (SAV) growth that year was considerable and that the SAV growth had made the Lake less desirable and less usable than previous years. The SAV that dominates the lake is Potomogeton crispus (curlyleaf pondweed). On August 20, 2004, a meeting was held by individuals who own property on Reshanau Lake to consider what options were available to make improvements to the quality of the Lake. Representatives from The DNR and the Rice Creek Watershed District were present and spoke about issues related to the Lake. In summary, the Lake is not in a desirable state. No objective measurements had been made on the Lake in some time; however, it is believed that the lake could be improved through the efforts of a variety of individuals and organizations. A lake management improvement partnership is being formed with property owners on Reshanau Lake, other users of Reshanau Lake, property owners in the contributing drainage area of Reshanau Lake, the Rice Creek Watershed District (RCWD), and other governmental and regulatory agencies with responsibility for Reshanau Lake. Figure 1 shows the drainage area for Reshanau Lake. On, October 2, 2004, a group of property owners met with a representative of the RCWD and Department of Natural Resources (DNR) to begin the preparation of a comprehensive plan to improve the quality of Reshanau Lake. II. Problem Statement Reshanau Lake is highly eutrophic (meaning that there is an excessive amount of phosphorus and algae growth). The lake also has a high density of curlyleaf pondweed growing throughout the basin. The curlyleaf pondweed has two main problems: 1st it grows to the surface and creates a canopy that is nearly impassable by recreational watercraft, 2nd it dies in late June to early July which will send a pulse of total phosphorus (TP) into the water column that triggers a nuisance algal bloom. This algal bloom turns the water dark green and inhibits any type of water contact activity. The City of Lino Lakes owns a park on the south shore that has a public swimming beach that gets very limited use partially because of the nuisance algal blooms. III Management Goals The management goal set for Reshanau Lake is to reduce the abundance of curlyleaf pondweed and increase the amount and diversity of native SAV species. Another goal is to reduce the in -lake phosphorus concentration to 60 parts per billion (ppb). This phosphorus level would reduce the frequency and duration of algal blooms and increase the recreational use of the lake. G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc2 Figure 1: Reshanau Lake Watershed Boundary fit I-. 0.2 0 0.2 0.4 Miles Reshanau Lake Management Plan • IV. History /Summary of Existing Data Reshanau Lake was formed by dredging the swampy area, roughly where the lake now exist, in the late 1960's and early 1970's. The material removed from the lake was used to make what is now Chomonix Golf course and to make build able lots on the lake's perimeter. For a number of years, the lake was treated annually by a commercial applier but was discontinued for some reason before 1995. Over the years individual property owners have applied some chemical treatments with marginal or no apparent success. Attempts have been made over the years to form an Association of property owners but have been unsuccessful. In 1995 a study of Reshanau Lake was conducted by Montgomery Watson (Attachment A), which provides some historical and benchmark data. This report shows that Reshanau Lake is Eutrophic (high in nutrients) and does not support swimming or other contact water activity according to Minnesota Pollution Control Agency (MPCA) standards. The report also suggests that the growth of the exotic curly -leaf pondweed contributes significant phosphorus to the lake. A summary of the 1995 lake monitoring report shows that the in -lake total phosphorus (TP) levels averaged 110 ug /L during the growing season. TP is the nutrient that drives algal productivity in most northern latitude states. This nutrient is generally the limiting factor for plant growth. Since this nutrient is often associated with man induced activities, it is almost always the nutrient that lake managers target to reduce the frequency and duration of algae blooms and to help control SAV growth. TP entering the lake is coming from four primary sources. Theses sources are County Ditch 25 (CD25) which enters on the east side of the lake, a small tributary creek which enters the lake on the south side, internal cycling of TP from the die off and decomposition of curlyleaf pondweed, and direct drainage from manicured lawn runoff and possible failing septic tanks. The early summer TP levels are 70 pg /L and peak at 140 µg /L in late July. This peak TP concentration coincides with the die -off and decomposition of curlyleaf pondweed in the lake. Looking back at the 1995 stream monitoring data also suggests that during the flashier stream flow period of July and August TP export from CD 25 is higher. The Chlorophyll -a (CHLA) concentration averaged 3911g /L during the growing season and was at a low of 11 p.g /L in early June and peaked at 121 µg /L in early August. CHLA measurement is a measurement of plant productivity in a lake. All vascular plants produce CHLA and this measurement is related to the amount of algae when a surface water sample is collected and analyzed. CHLA concentrations generally increase with an increase in TP concentrations. The CHLA cycle is also attributable to the die -off and G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc4 Reshanau Lake Management Plan decomposition of curlyleaf pondweed in the lake. Secchi disk transparency (SD) is the surrogate measurement for the depth that light penetrates the water column. This measurement is related to the depth of submerged aquatic plant growth. Typically plants will grow to a depth of 1.5 times the SD reading. SD readings can be affected by either sediment in the water column or by algae growth as measured by CHLA. The SD mirrors the CHLA concentrations. This suggests that water transparency is directly related to CHLA production and reduction of CHLA concentrations will improve water clarity. V. Situational Analysis Currently, no formal or informal group exists which is capable of making any decisions regarding the approval of any proposed plan regarding the Lake. There are at least three options that are being considered. 1) To establish an Association of Property Owners on the Lake and collect money to do whatever the group decides the money should be spent on. 2) To establish a "Lake Improvement District" (LID) which is a formal entity recognized and approved by the county and the city, which allows for the collection of funds through property tax bills, to be spent on studies and projects which benefit the district. There are a number of issues to be dealt with if we choose this option. 3) To ask the Rice Creek Watershed District to establish a "Special Taxing District" to collect money to administer this plan. In January 2005, a list of 153 property owners on Reshanau Lake was obtained from the Anoka County Geographical Informational Services (GIS) department. Recently, a mailing was sent to all of these property owners which outlines what is being proposed in this plan. It is our intent to contact and meet each of these property owners individually to obtain their approval of this plan in the form of a signed petition to be presented to the Rice Creek Watershed Board. VI. Objective The main objective is to form a cooperative effort between lakeshore property owners and the RCWD to improve the overall water quality and aquatic plant community in Reshanau Lake. Currently the lake is not a community asset because of excessive algal blooms. With some remedial activities, the lake can become an asset to the community and downstream water bodies. G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc5 • Reshanau Lake Management Plan The plan proposes a goal that can be measured in quantitative terms such as a "Tropical State Index (TSI). The TSI is a measurement used by lake managers to describe a condition of a lake based on three variables: Total Phosphorus, {(TP), nutrient concentration) }, Secchi Transparency {(SD), water clarity) }, and Chlorophyll -a {(CHLA), algae concentration) }.This measurement was quantified during the 1995 study and was determined to be "68." The MPCA (1990) classifies lakes based on TSI into the following categories, 1) lakes which fully support swimming, 2) lakes which partially support swimming, and 3) lakes which are non - supporting of swimming. The 1995 measurement for Reshanau Lake of "68" categorizes the lake as a "lake which is non - supporting of swimming." Assuming that no more recent data exists, and that quality of the lake has probably not improved and likely decreased since the 1995 study, we propose establishing a summertime TSI rating of less than 57.This would correspond to a TP concentration of 60 ppb, SD of >/= 1.2 m, and a CHLA concentration of < 25 ppb. Achieving a growing season average TSI of 62 or less would characterize the lake as partially supporting swimming. Both the duration and frequency of algal blooms would be reduced to less than 25% of the summer. We would like to achieve this goal by 2008. • The following activities were considered to varying degrees during the last six months: Harvest rough fish Harvest curly leaf pondweed Obtain benchmark data Controlling the migration of rough fish from other lakes Chemical treatments to try eradication of curly leaf pondweed Shoreline restoration Controlling lake elevations Communication and education Street and storm sewer issues All of the above management practices alone will not significantly change the water quality of the lake. A combination of management strategies will need to be implemented over a period of time to achieve the desired results. It was decided to focus on those activities we perceive to provide the greatest potential for a positive impact on the lake and the surrounding watershed. And, begin a more comprehensive program of monitoring the Lake and input sources to identify areas to focus on in the future. The specific strategies of the Plan are as follows: G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc6 Reshanau Lake Management Plan As appropriate, begin communicating to, and educating, individuals and property owners in the Lake Reshanau watershed as to how their activities may positively or negatively impact the quality of the lake and watershed. Coordinate with the Public education coordinator from RCWD to distribute literature about good housekeeping practices about preventing nutrients from washing off into the lake. Conducting storm drain stenciling to further awareness about the connection to the lake via storm sewers. VII. Budget and Timeframe This plan focuses on a three -year timeframe starting in the summer of 2006 and ending in the fall of 2008. It is expected that if these programs are effective at improving the water quality of Reshanau Lake this plan may be revisited and modified to reflect the current thinking at that time. However, if at the end of three years or if it is determined that prior to the end of three years, that these program are having no positive effect on Reshanau Lake, they will be discontinued and no additional funding will be provided. Line Items 2006 2007 2008 1) Fish Harvest $8,000 2) Chemical $60,000 $50,000 $40,000 Treatment 3) Monitor Lake and RCWD(in -kind) inflows 4) Algae Treatment $1,000 $1,000 $1,000 5) Education and $500 $500 $500 Communication Material 6) Aquatic plant RCWD (in -kind) mapping — twice a year Total VIII. Organization $69,500 $51,500 $41,500 A group of property owners have been operating as a "steering committee" since the fall of 2004. They have been responsible for the compilation of this G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005- 04- 13 \Reshanau mgmt plan.doc8 • Reshanau Lake Management Plan "Plan" with the assistance of RCWD staff and other affected entities. They have been responsible for facilitating communications between the property owners and RCWD. Their participation is voluntary and any property owner on Reshanau Lake is welcome to participate. IX. Funding The Plan suggests that primary funding for these projects comes from the individual property owners on Reshanau Lake either voluntarily or through the formation of some sort of Taxing District such as a Lake Improvement District (LID) or a special taxing district through the Rice Creek Watershed District. The creation of these Taxing Districts would facilitate the collection of funds and ensure greater participation. Secondary funding for Plan projects will come from various governmental, regulatory, benefiting entities of Reshanau Lake. Including, but not limited to, the Rice Creek Watershed District, the City of Lino Lakes, the County of Anoka, the DNR, and others to be determined. X. Summary The Reshanau Lake homeowners are asking that The RCWD review this Plan to ensure that it is consistent with other lake management efforts within our area and to advise and assist in the implementation of this plan. The Reshanau Lake homeowners would like assistance in monitoring water quality, documenting aquatic plant communities, monitoring inflow sources, and securing supplemental funding. While the primary focus of this plan is a three -year timeframe, we do not want to close our eyes to other opportunities, which may present themselves now and in the future, which may positively impact Reshanau Lake. These include but are not limited to: The possible acquisition of land for the construction of a holding pond. The use of mechanical and or electronic fish barriers "Demo" Rain Gardens Means of controlling lake elevation Shoreline restoration projects G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc9 Reshanau Lake Management Plan I) Conduct intensive lake- monitoring program in 2005 to inventory current conditions and propose specific strategies to mitigate problems. This monitoring will include in -lake water chemistry, stream flows and chemistry and lake SAV maps during June and August. This data will be needed to get an approved lake management plan to the MN DNR to implement a chemical treatment application for SAV beyond the 15 % allowed under State law. 2) Early in 2005, contract with a commercial fisherman to harvest the rough fish from Lake Reshanau and other Lakes in the watershed as determined by the Rice Creek Watershed District. The necessary permits have been secured and they are currently tying to locate the best location to conduct the harvest(s). The rough fish population in the Chain of lakes is high. These fish consume SAV and distribute phosphorus rich lake sediment into the water column during feeding activities. The suspended sediment reduces water clarity and increases available TP for algae growth. 3) Investigate the potential for placing a fish barrier on the outlet of the lake at west shadow Lake road. 4) Chemically treat the entire lake with a herbicide to kill the non - native curly leaf pondweed. Chemical treatment could begin in 2006 with annual applications occurring each spring through 2008 to treat the residual curlyleaf turions pending MN DNR approval of the Lake Management Plan. After three years the treatments should be reconsidered in the hope that native vegetation will have re- established itself and that the curly leaf pondweed will have diminished to a point that widespread commercial treatment will not be necessary. 5) Upon completion of the treatment for curly leaf pondweed and in conjunction with the algae bloom resulting from the decomposition of the curly leaf pondweed, we propose to commercially treat the algae with copper sulfate. 6) If the above lake management strategies are successful there is a potential for excessive growth of native vegetation. If growth of native plants reaches nuisance levels a separate management plan will be written in the future to address these issues. In 2005, begin a comprehensive plan to monitor the Lake to determine what impact these strategies are having on the existence of the non - native curly leaf pondweed, and the re- establishment of native aquatic vegetation. In addition, begin testing more specific measurements like phosphorus levels, chlorophyll, dissolved oxygen, and water clarity to quantify progress. G: \Admin \Board \Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc7 • Reshanau Lake Management Plan Facilitating adequate storm and sewer systems in the area surrounding Reshanau Lake All of these and others will require additional research to determine there applicability to water quality issues and how and what funding may be available. G: \Admin \Board\Agenda Paks \2005 Agenda Paks \2005 -04 -13 \Reshanau mgmt plan.doc10 MEMORANDUM Rice Creek Watershed District To: Marty Asleson From: Matthew Kocian (763- 398 -3075) Subject: Reshanau Lake — Curlyleaf Pondweed Control Date: 7/21/2008 Background / Discussion Reshanau Lake, located in Lino Lakes, MN, supports a substantial population of curlyleaf pondweed (Potamogeton crispus). Curlyleaf pondweed is a non - native plant species that is characterized by its unusual life - cycle. The submerged plant begins growing while ice is still present on lakes. It dies around mid- summer, at which time the plant decomposes in the water column. It can grow in dense stands, often outcompeting native plants. In cases where the density is very high, as in Reshanau Lake, the decomposition of the plant material at mid - summer releases significant amounts of phosphorus. Excess phosphorus fuels algal growth and can result in poor water clarity. Dense curlyleaf populations can also inhibit recreation by forming surface mats. Aquatic vegetation surveys in Reshanau Lake have found curlyleaf present at roughly 95% of survey sites, and at all depths. Many sites exhibited high curlyleaf density. Very little native aquatic vegetation was found during surveys. Ongoing Control Herbicides have been used to control curlyleaf pondweed in Reshanau Lake since 2005. Treatments have been effective at controlling curlyleaf; each of the 130 monitoring stations does not support curlyleaf after herbicide treatment. In 2008, the cost of the chemical treatment was $35, 814. The cost of the treatment was split 50/50 between the Rice Creek Watershed District and residents of Reshanau Lake. The vendor responsible for the treatment has warned of future price increases, as demand for the chemical increases. • •