Sibley 18-0404-00 CROW WING COUNTY

Lake Water Quality

Summary

Sibley is located 1.5 miles west of Pequot Lakes, MN in Crow Wing County. It is a long and narrow lake that stretches north to south and covers 433 acres (Table 1).

Sibley has two inlets and one outlet, which classify it as a drainage lake. Water enters Sibley from the Mayo creek and an unnamed creek on the west side. After exiting through the Sibley Lake Dam water moves into Mayo Lake and eventually the Gull Lake Chain of Lakes.

Water quality data have been collected on Sibley in 1987-2012 (Tables 2 & 3). These data show that the lake is eutrophic (TSI = 56) with algae blooms in late summer.

The missions of the Sibley Area Association and Sibley LID has many purposes, including; restoring and maintaining water purity to the lake, increase and improve fishing conditions on the lake, improve property value and quality of life, preservation of the shoreline and wilderness, and represent the best interest of its members with government and taxing authority. The Association is involved in many activities including water quality monitoring and educating the public.

Table 1. Sibley location and key physical characteristics.

Location Data Physical Characteristics MN Lake ID: 18-0404-00 Surface area (acres): 433 County: Crow Wing and Cass Littoral area (acres): 255 Ecoregion: North Lakes and Forests % Littoral area: 59 Major Drainage Basin: Upper Mississippi River Max depth (ft), (m): 40, 12.2 Latitude/Longitude: 46.5930/-94.3243 Inlets: 2 Invasive Species: None Outlets: 1

Public Accesses: 1

Table 2. Availability of primary data types for Sibley. Data Availability

Transparency data Excellent data source from 1987-2012.

Chemical data Excellent data source from 1988, 2003-2004, 2006-2012.

Inlet/Outlet data Limited data source from 2011.

Recommendations For recommendations refer to page 19.

RMB Environmental Laboratories, Inc. 1 of 21 2013 Sibley Lake Map

Figure 1. Map of Sibley with 2010 aerial imagery and illustrations of lake depth contour lines, sample site locations, inlets and outlets, and public access points. The light green areas in the lake illustrate the littoral zone, where the sunlight can usually reach the lake bottom, allowing aquatic plants to grow.

Table 3. Monitoring programs and associated monitoring sites. Monitoring programs include the Minnesota Pollution Control Agency Lake Monitoring Program (MPCA), Citizen Lake Monitoring Program (CLMP), Crow Wing County Citizens Monitoring (CWCCM), Lake Trend Monitoring (LTM), Outdoor Corps Lake Monitoring (OCLM) and RMB Environmental Laboratories Lakes Program (RMBEL). Lake Site Depth (ft) Monitoring Programs 100 5 MPCA:1988 201* Primary Site 25 CLMP: 1987-1989, 1995, 2008-2011; CWCCM: 2008-2009; LTM: 2004; MPCA: 1988; OCLM: 2003; RMBEL: 2003 202 25 CLMP: 1987-1999, 2001-2002 203 40 CLMP: 1988-2004 204 25 CLMP: 1988-1994, 1996-1999, 2001-2002; RMBEL: 2006-2007 205 5 RMBEL: 2006-2007 206 10 RMBEL: 2006-2007 207 20 RMBEL: 2006-2007

RMB Environmental Laboratories, Inc. 2 of 21 2013 Sibley Average Water Quality Statistics

The information below describes available chemical data for Sibley through 2012 (Table 4). All data are from the primary site 201 from 1987-1989, 1995, 2003-2004, and 2008-2012.

Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation and geology. The MPCA has developed a way to determine the "average range" of water quality expected for lakes in each ecoregion. For more information on ecoregions and expected water quality ranges, see page 11.

Table 4. Water quality means compared to ecoregion ranges and impaired waters standard. Impaired Ecoregion Waters Parameter Mean Range1 Standard2 Interpretation Total phosphorus (ug/L) 33.7 14 – 27 > 30 Results are above the expected 3 Chlorophyll a (ug/L) 19.3 4 – 10 > 9 range for the ecoregion, and Chlorophyll a max (ug/L) 34 < 15 above the Impaired Waters Standards. Secchi depth (ft) 5.6 8 – 15 < 6.5 Dissolved oxygen Dimictic Dissolved oxygen depth profiles see page 8 show that the deep areas of the lake are anoxic in late summer. Total Kjeldahl Nitrogen 0.78 <0.4 – 0.75 Indicates insufficient nitrogen to (mg/L) support summer nitrogen- induced algae blooms. Alkalinity (mg/L) 113.6 40 – 140 Indicates a low sensitivity to acid rain and a good buffering capacity. Color (Pt-Co Units) 25.5 10 – 35 Indicates turbid water with possible tannins (brown stain). pH 8.5 7.2 – 8.3 Indicates a hardwater lake. Lake water pH less than 6.5 can affect fish spawning and the solubility of metals in the water. Chloride (mg/L) 4.5 0.6 – 1.2 Above the expected range for the ecoregion. Total Suspended 4.7 <1 – 2 Above the expected range for Solids (mg/L) the ecoregion Conductivity (umhos/cm) 264.5 50 – 250 Above the expected range for the ecoregion. Total Nitrogen : Total 23:1 25:1 – 35:1 Indicates the lake is Phosphorus phosphorus limited, which means that algae growth is limited by the amount of phosphorus in the lake. 1The ecoregion range is the 25th-75th percentile of summer means from ecoregion reference lakes 2For further information regarding the Impaired Waters Assessment program, refer to http://www.pca.state.mn.us/water/tmdl/index.html 3Chlorophyll a measurements have been corrected for pheophytin Units: 1 mg/L (ppm) = 1,000 ug/L (ppb)

RMB Environmental Laboratories, Inc. 3 of 21 2013 Sibley Water Quality Characteristics - Historical Means and Ranges

Table 5. Water quality means and ranges for primary sites.

Primary Site Site Site Site Parameters 201 202 203 204 Total Phosphorus Mean (ug/L): 33.7 Total Phosphorus Min: 19 Total Phosphorus Max: 65 Number of Observations: 46 Chlorophyll a Mean (ug/L): 19.3 Chlorophyll-a Min: 5 Chlorophyll-a Max: 34 Number of Observations: 46 Secchi Depth Mean (ft): 5.6 6.5 5.5 6.1 Secchi Depth Min: 3.0 3.5 3.0 3.0 Secchi Depth Max: 21.0 12.0 9.0 12.0 Number of Observations: 101 115 199 95

FigureFigure 2. Sibley 2. Lake total “insert” phosphorus, total phosphorus, chlorophyll chlorophyll a and transparency a and transparency historical ranges.historical The ranges. arrow The arrow representsrepresents the therange range and and the theblack black dot dotrepresents represents the thehistorical historical mean mean (Primary (Primary Site Site 201). xxx). Figure Figure adapted adapted after Moore and Thornton, [Ed.]. 1988. Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/5-88-002) after Moore and Thornton, [Ed.]. 1988. Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/5-88-002)

RMB Environmental Laboratories, Inc. 4 of 21 2013 Sibley Transparency (Secchi Depth)

Transparency is how easily light can pass through a substance. In lakes it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, so they are only able to grow in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The transparency varies year to year due to changes in weather, precipitation, lake use, flooding, temperature, lake levels, etc.

The annual mean transparency in Sibley Lake ranges from 3.7 to 9.8 feet (Figure 3). The transparency throughout the lake appears to be relatively uniform, with similar transparency occurring at the deepest spots of the lake (sites 201, 202, and 204).

Sites 201, 202, and 204 in the deepest parts of the lake consistently have better transparency than site 203 in the more southern, shallower portion of the lake(Figure 3). There is a 15-30 ft. depth difference between the shallow and deep sites, which could explain this pattern. Transparency monitoring should be continued annually at sites 201 and 203 in order to track water quality changes.

12 Transparency: Annual Means Site 201 Site 202 10 Site 203 Site 204 8 (ft)

Mean

6 Depth

4 Secchi

2

0

Date

Figure 3. Annual mean transparency compared to long-term mean transparency.

Sibley transparency ranges from 3 to 21 ft at the primary site (201). Figure 4 shows the seasonal transparency dynamics. The maximum Secchi reading is usually obtained in early summer. Sibley transparency is high in May and then declines through August. If transparency readings were taken in October it would most likely rebound after fall turnover. This transparency dynamic is typical of a Minnesota lake. The dynamics have to do with algae and zooplankton population dynamics, and lake turnover.

It is important for lake residents to understand the seasonal transparency dynamics in their lake so that they are not worried about why their transparency is lower in August than it is in June. It is typical for a lake to vary in transparency throughout the summer.

RMB Environmental Laboratories, Inc. 5 of 21 2013 Sibley Seasonal Transparency Dynamics 1987 25 1988 1989 1995 20 2003 2004 2008 (ft) 15 2009 2010 Depth

2011 10 2012

Secchi Poly. (Pattern)

5

0

Date Figure 4. Seasonal transparency dynamics and year to year comparison (Primary Site 201). The black line represents the pattern in the data.

User Perceptions

When volunteers collect Secchi depth readings, they record their perceptions of the water based on the physical appearance and the recreational suitability. These perceptions can be compared to water quality parameters to see how the lake "user" would experience the lake at that time. Looking at transparency data, as the Secchi depth decreases the perception of the lake's physical appearance rating decreases. Sibley was rated as having "definite algae" 46% of the time by samplers at site 201 between 1987-1989, 1995, 2004, and 2008-2012(Figure 5).

Physical Appearance Rating 2% 6% 10% 6% Crystal clear water

36% Not quite crystal clear – a little algae visible

46% Definite algae – green, yellow, or brown color apparent 36% 10% High algae levels with limited clarity and/or mild odor apparent

46% 2% Severely high algae levels

Figure 5. Sibley physical appearance ratings by samplers.

RMB Environmental Laboratories, Inc. 6 of 21 2013 Sibley As the Secchi depth decreases, the perception of recreational suitability of the lake decreases. Sibley was rated as having "very minor aesthetic problems" 59% of the time from 1987-1989, 1995, 2004, and 2008-2012 (Figure 6).

Recreational Suitability Rating 1% 11% 16% 16% Beautiful, could not be better

59% Very minor aesthetic problems; excellent for 13% swimming, boating

13% Swimming and aesthetic enjoyment of the lake slightly impaired because of algae levels

11% Desire to swim and level of enjoyment of the lake substantially reduced because of algae levels

1% Swimming and aesthetic enjoyment of the lake 59% nearly impossible because of algae levels

Figure 6. Recreational suitability rating, as rated by the volunteer monitor.

Total Phosphorus

Sibley is phosphorus Total Phosphorus limited, which means that 70 Eutrophic algae and aquatic plant 60 growth is dependent upon 1988 available phosphorus. 50 2003 (ug/L) 2004 Total phosphorus was 40 2008 evaluated in Sibley in 1998, 2003-2004, and 2008-2012. 30 2009 Phosphorus 2010 The higher phosphorus 20 Mesotrophic readings in spring and fall 2011 are most likely due to Total 10 Oligotrophic 2012 turnover. The majority of the data points fall into the 0 eutrophic range (Figure 7).

Phosphorus should continue to be monitored to Figure 7. Historical total phosphorus concentrations (ug/L) for Sibley site 201. track any future changes in water quality.

RMB Environmental Laboratories, Inc. 7 of 21 2013 Sibley Chlorophyll a

Chlorophyll a is the Chlorophyll a pigment that makes 70 plants and algae 60 1988 green. Chlorophyll 2003 a is tested in lakes 50 2004 to determine the

(ug/L) 2008

algae concentration a

40 or how "green" the 2009 water is. 30 2010 Chlorophyll a 2011 20 concentrations Chlorophyll 2012 greater than 10 Minor Algae 10 ug/L are perceived Nuisance Algae as a mild algae bloom, while 0 concentrations greater than 20 Date ug/L are perceived as a nuisance. Figure 8. Chlorophyll a concentrations (ug/L) for Sibley at site 201.

Chlorophyll a was evaluated in Sibley at site 201 from 1988, 2003-2004, 2008-2012 (Figure 8). Chlorophyll a concentrations remained above 10 ug/L on all but 7 sample dates, indicating green water most of the summer. A majority of the sample dates have chlorophyll a values greater than 20 ug/L. Those dates that exceed 20 ug/L are considered to have a nuisance algae bloom occurring. There was not much variation over the years monitored and chlorophyll a concentrations remained relatively high all summer.

Dissolved Oxygen

Dissolved Oxygen (mg/L) Dissolved Oxygen (DO) is the amount of oxygen 024681012 dissolved in lake water. Oxygen is necessary for all 0 living organisms to survive except for some bacteria. Living organisms breathe in oxygen that is dissolved in the water. Dissolved oxygen levels of <5 mg/L are 2 typically avoided by game fisheries.

Sibley is a moderately shallow lake, with a maximum depth of 40 ft. Dissolved oxygen profiles from data 4 collected in 2004 at site 201 show stratification (m) developing mid-summer. The thermocline occurs between 4 and 6 meters (13.1 and 19.7 feet), which

Depth 6 means that gamefish will be scarce below this depth. Figure 9 is a representative DO profile for Sibley and it illustrates stratification in the summer of 2004 at site 201.

8 5/10/2004 7/12/2004 8/9/2004 10 Figure 9. Dissolved oxygen profile for Sibley 9/14/2004 Lake

RMB Environmental Laboratories, Inc. 8 of 21 2013 Sibley Trophic State Index (TSI)

Table 6. Trophic State Index for site 201. TSI is a standard measure or means for calculating the trophic status or productivity of a lake. More specifically, Trophic State Index Site 201 it is the total weight of living algae (algae biomass) in a TSI Total Phosphorus 55 waterbody at a specific location and time. Three TSI Chlorophyll-a 60 variables, chlorophyll a, Secchi depth, and total TSI Secchi 52 phosphorus, independently estimate algal biomass. TSI Mean 56

Trophic State: Eutrophic Phosphorus (nutrients), chlorophyll a (algae concentration) and Secchi depth (transparency) are Numbers represent the mean TSI for each related. As phosphorus increases, there is more food parameter. available for algae, resulting in increased algal concentrations. When algal concentrations increase, 100 the water becomes less transparent and the Secchi depth decreases. If all three TSI numbers are within a Hypereutrophic few points of each other, they are strongly related. If they are different, there are other dynamics 70 influencing the lake’s productivity, and TSI Eutrophic mean should not be reported for the lake. Sibley 50 The mean TSI for Sibley falls into the Mesotrophic eutrophic range (Figure 10). The chlorophyll a TSI is higher than the phosphorus and Secchi (Table 6). This 40 could be due to loss of rooted vegetation, which is leaving available phosphorus to be taken up by algae, not rooted plants. Oligotrophic

Eutrophic lakes (TSI 50-70) are characteristic of "green" water most of the summer. "Eu" means true and the root "trophy" means nutrients therefore, eutrophic 0 literally means true nutrients or truly nutrient rich (phosphorus). Eutrophic lakes are usually shallow, and Figure 10. Trophic state index chart are found where the soils are fertile. Eutrophic lakes with corresponding trophic status. usually have abundant aquatic plants and algae.

Table 7. Trophic state index attributes and their corresponding fisheries and recreation characteristics. TSI Attributes Fisheries & Recreation <30 Oligotrophy: Clear water, oxygen throughout Trout fisheries dominate the year at the bottom of the lake, very deep cold water. 30-40 Bottom of shallower lakes may become anoxic Trout fisheries in deep lakes only. Walleye, (no oxygen). Cisco present. 40-50 Mesotrophy: Water moderately clear most of No oxygen at the bottom of the lake results in the summer. May be "greener" in late summer. loss of trout. Walleye may predominate. 50-60 Eutrophy: Algae and aquatic plant problems Warm-water fisheries only. Bass may possible. "Green" water most of the year. dominate. 60-70 Blue-green algae dominate, algal scums and Dense algae and aquatic plants. Low water aquatic plant problems. clarity may discourage swimming and boating. 70-80 Hypereutrophy: Dense algae and aquatic Water is not suitable for recreation. plants. >80 Algal scums, few aquatic plants Rough fish (carp) dominate; summer fish kills possible Source: Carlson, R.E. 1997. A trophic state index for lakes. Limnology and Oceanography. 22:361-369.

RMB Environmental Laboratories, Inc. 9 of 21 2013 Sibley Trend Analysis

For detecting trends, a minimum of 8-10 years of data with 4 or more readings per season are recommended. Minimum confidence accepted by the MPCA is 90%. This means that there is a 90% chance that the data are showing a true trend and a 10% chance that the trend is a random result of the data. Only short-term trends can be determined with just a few years of data, because there can be different wet years and dry years, water levels, weather, etc, that affect the water quality naturally.

Sibley had enough data to perform a trend analysis on Transparency (Table 8). The data was analyzed using the Mann Kendall Trend Analysis.

Table 8. Trend analysis for site 203. Lake Site Parameter Date Range Trend Probability 203 Transparency 1989-2004 Declining 99% All sites Chlorophyll a -- Insufficient data -- All sites Total Phosphorus -- Insufficient data --

Sibley LakeTransparency Trend 8

7

6 (ft)

5

4 Depth

3 Seechi 2

1

0

Figure 11. Transparency (feet) trend for site 203 from 1989-2004.

The Sibley Lake transparency trend shows evidence of declining water quality (Figure 11), although the data stops in 2004. There is no current data to see if this declining trend continued. There is insufficient data for a trend analysis for chlorophyll a and total phosphorus in Sibley Lake. Monitoring of all three parameters should continue so that these trends can be tracked in future years.

RMB Environmental Laboratories, Inc. 10 of 21 2013 Sibley Ecoregion Comparisons

Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation and geology (Figure 12). The MPCA has developed a way to determine the "average range" of water quality expected for lakes in each ecoregion. From 1985-1988, the MPCA evaluated the lake water quality for reference lakes. These reference lakes are not considered pristine, but are considered to have little human impact and therefore are representative of the typical lakes within the ecoregion. The "average range" refers to the 25th - 75th percentile range for data within each ecoregion. For the purpose of this graphical representation, the means of the reference lake data sets were used.

Sibley is in the Northern Lakes and Forest Ecoregion. The mean total phosphorus, chlorophyll a and transparency (Secchi depth) for Sibley are poorer than the ecoregion ranges (Figure 13). Figure 12. Minnesota Ecoregions.

40 70 0

35 60 5 30 50 increased algae 25 10 40 20 30 15 15 Secchi depth (ft) 20

Chlorophyll-a (ug/L, ppb) (ug/L, Chlorophyll-a 10 Total Phosphorus (ug/L, Total Phosphorus ppb) 20 10 crystal 5 clear

0 0 25 NLF Sibley NLF Sibley NLF Sibley Ecoregion Ecoregion Ecoregion

Figure 13. Sibley ranges compared to Northern Lakes and Forest Ecoregion ranges. The Sibley total phosphorus and chlorophyll a ranges are from 46 data points collected in May-September of 1988, 2003- 2004, and 2008-2011. The Sibley Secchi depth range is from 101 data points collected in May-September of 1987-1989, 1995, 2003-2004, 2008-2012.

RMB Environmental Laboratories, Inc. 11 of 21 2013 Sibley Lakeshed Data and Interpretations

Lakeshed Understanding a lakeshed requires an understanding of basic hydrology. A watershed is defined as all land and water surface area that contribute excess water to a defined point. The MN DNR has delineated three basic scales of watersheds (from large to small): 1) basins, 2) major watersheds, and 3) minor watersheds.

The Crow Wing River Major Watershed is one of the watersheds that make up the Upper Mississippi River Basin, which drains south to the Gulf of Mexico (Figure 14). This major watershed is made up of 136 minor watersheds. Sibley is located in minor watershed 12126 (Figure 15).

Figure 14. Crow Wing River Watershed. Figure 15. Minor Watershed 12126.

The MN DNR also has evaluated catchments for each individual lake with greater than 100 acres surface area. These lakesheds (catchments) are the “building blocks” for the larger scale watersheds. Sibley falls within lakeshed 1212601 (Figure 16). Though very useful for displaying the land and water that contribute directly to a lake, lakesheds are not always true watersheds because they may not show the water flowing into a lake from upstream streams or rivers. While some lakes may have only one or two upstream lakesheds draining into them, others may be connected to a large number of lakesheds, reflecting a larger drainage area via stream or river networks. For further discussion of Sibley’s watershed, containing all the lakesheds upstream of the Sibley lakeshed, see page 17. The data interpretation of the Sibley lakeshed

Figure 16. Sibley lakeshed (1212601) with land ownership, lakes, wetlands, and rivers illustrated.

RMB Environmental Laboratories, Inc. 12 of 21 2013 Sibley includes only the immediate lakeshed as this area is the land surface that flows directly into Sibley. The lakeshed vitals table identifies where to focus organizational and management efforts for each lake (Table 9). Criteria were developed using limnological concepts to determine the effect to lake water quality.

KEY Possibly detrimental to the lake Warrants attention Beneficial to the lake

Table 9. Sibley lakeshed vitals table. Lakeshed Vitals Rating Lake Area 433 acres descriptive Littoral Zone Area 255 acres descriptive Lake Max Depth 40 feet descriptive Lake Mean Depth NA NA Water Residence Time NA NA Miles of Stream 1.5 descriptive Inlets 2 Outlets 1 Major Watershed 12 – Crow Wing River descriptive Minor Watershed 12126 descriptive Lakeshed 1212601 descriptive Ecoregion Northern Lakes and Forests descriptive Total Lakeshed to Lake Area Ratio (total 8:1 lakeshed includes lake area) Standard Watershed to Lake Basin Ratio 65:1 (standard watershed includes lake areas) Wetland Coverage (NWI) 6.3% Aquatic Invasive Species None as of 2012 Public Drainage Ditches None Public Lake Accesses 1 Miles of Shoreline 9.29 descriptive Shoreline Development Index 3.2 Public Land to Private Land Ratio 0.1:1 Development Classification General Development Miles of Road 33.3 descriptive Municipalities in lakeshed Pequot Lakes County Forest Management: Forestry Practices http://www.co.crow- wing.mn.us/index.aspx?NID=261 Feedlots None Individual Subsurface Sewage Treatment Sewage Management Systems (Inspection and assessment required for all permits and property transfers within the Shoreland Protection Zone) Lake Management Plan Healthy Lakes and Rivers Program, 1999 Lake Vegetation Survey/Plan None

RMB Environmental Laboratories, Inc. 13 of 21 2013 Sibley Land Cover / Land Use

The activities that occur on the land within the lakeshed can greatly impact a lake. Land use planning helps ensure the use of land resources in an organized fashion so that the needs of the present and future generations can be best addressed. The basic purpose of land use planning is to ensure that each area of land will be used in a manner that provides maximum social benefits without degradation of the land resource.

Changes in land use, and ultimately land cover, impact the hydrology of a lakeshed. Land cover is also directly related to the land’s ability to absorb and store water rather than cause it to flow overland (gathering nutrients and sediment as it moves) towards the lowest point, typically the lake. Impervious intensity describes the land’s inability to absorb water, the higher the % impervious intensity the more area that water cannot penetrate in to the soils. Monitoring the changes in land use can assist in future planning procedures to address the needs of future generations.

Phosphorus export, which is the main cause of lake eutrophication, depends on the type of land cover occurring in the lakeshed. Figure 17 depicts the land cover in Sibley’s lakeshed.

The National Land Cover Dataset has online records of land cover statistics from years 2001 and 2006. Although some of this data is 12 years old, it is the Figure 17. Sibley lakeshed (1212601) land cover most recent data set that is comparable. (http://mrlc.gov) Table 10 describes Sibley Lake’s lakeshed land cover statistics and percent change from 2001 to 2006. Due to the many factors that influence demographics, one cannot determine with certainty the projected statistics over the next 10, 20, 30+ years, but one can see the transitions occurring within the last 12 years within the lakeshed.

RMB Environmental Laboratories, Inc. 14 of 21 2013 Sibley Table 10. Sibley’s lakeshed land cover statistics and % change from 2001 to 2006 (http://mrlc.gov) 2001 2006 % Change Land Cover Acres Percent Acres Percent 2001 to 2006 Agriculture 518 11.69 520 11.72 0.3% Increase Forest 1448 32.67 1439 32.45 0.7% Decrease Grass/Shrub/Wetland 1627 36.71 1625 36.65 0.2% Decrease Water 421 9.50 422 9.52 0.2% Increase Urban 420 9.48 428 9.65 1.8% Increase

Impervious Intensity % 0-19 274 6.19 272 6.14 0.7% Decrease 20-49 146 3.29 150 3.37 2.4% Increase 50-79 0 0 3 0.06 300% Increase 80-100 0 0 4 0.08 400% Increase

Total Area 4433 4433 Total Impervious Area 420 9.48 428 9.65 1.8% Increase (Percent Impervious Area Excludes Water Area)

Demographics

Sibley is classified as a general development lake. General development lakes usually have more than 225 acres of water per mile of shoreline, 25 dwellings per mile of shoreline, and are more than 15 feet deep.

The Minnesota Department of Administration Geographic and Demographic Analysis Division extrapolated future population in 5- year increments out to 2035. Compared to Crow Wing County as a whole, the City of Pequot Lakes has a much lower extrapolated growth projection (Figure 18). (source:http://www.demography.state.mn.us/resource.html?Id=19332)

Figure 18. Population Population Growth Projection growth projection for the City of Pequot 40% City of Pequot Lakes; 2006 population: 1980 Lakes and Crow Wing 35% Crow Wing County total; 2006 population: 61,038 County. 30% 25% 20%

Percent 15% 10%

5% 0% 2006 2010 2015 2020 2025 2030 2035 Year

RMB Environmental Laboratories, Inc. 15 of 21 2013 Sibley Lakeshed Water Quality Protection Strategy

Each lakeshed has a different makeup of public and private lands. Looking in more detail at the makeup of these lands can give insight on where to focus protection efforts. The protected lands (easements, wetlands, public land) are the future water quality infrastructure for the lake. Developed land and agriculture have the highest phosphorus runoff coefficients, so this land should be minimized for water quality protection.

The majority of the land within Sibley’s lakeshed is privately owned and composed of forested uplands (Table 11). In addition, a large portion of land found within the “other” category was verified as being forested. This land can be the focus of development and protection efforts in the lakeshed.

Table 11. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and restoration in the lakeshed (Sources: Crow Wing County parcel data, National Wetlands Inventory, and the 2006 National Land Cover Dataset). Private (77%) 10% Public (13%) Forested Open Developed Agriculture Uplands Other Wetlands Water County State Federal Land Use (%) 5.8 9.7 25.1 31.9 4.5 10 9.5 3.4 0.1 Runoff Coefficient 0.45 – 1.5 0.26 – 0.9 0.09 0.09 0.09 0.09 0.09 Lbs of phosphorus/acre/year Estimated Phosphorus Loading 115 – 384 112 – 389 100 18 34 9 <1 Acreage x runoff coefficient

Focus of Open, develop- pasture, Focused on grass- Description Cropland ment and Protected Shoreland land, protection shrub- efforts land

Forest stewardship Potential rd Protected by Restore planning, 3 County Phase 3 Shoreline party State National wetlands; Wetland Tax Forfeit restoration certification, Conservation Forest Forest Discussion CRP Lands SFIA, local Act Items woodland cooperatives

DNR Fisheries approach for lake protection and restoration

Credit: Peter Jacobson and Michael Duval, Minnesota DNR Fisheries

In an effort to prioritize protection and restoration efforts of fishery lakes, the MN DNR has developed a ranking system by separating lakes into two categories, those needing protection and those needing restoration. Modeling by the DNR Fisheries Research Unit suggests that total phosphorus concentrations increase significantly over natural concentrations in lakes that have watershed with disturbance greater than 25%. Therefore, lakes with watersheds that have less than 25% disturbance need protection and lakes with more than 25% disturbance need restoration (Table 12). Watershed disturbance was defined as having urban, agricultural and mining land uses. Watershed protection is defined as publicly owned land or conservation easement.

RMB Environmental Laboratories, Inc. 16 of 21 2013 Sibley Table 12. Suggested approaches for watershed protection and restoration of DNR-managed fish lakes in Minnesota. Watershed Watershed Management Disturbance Protected Comments Type (%) (%) Sufficiently protected -- Water quality supports healthy and > 75% Vigilance diverse native fish communities. Keep public lands protected.

< 25% Excellent candidates for protection -- Water quality can be maintained in a range that supports healthy and diverse native < 75% Protection fish communities. Disturbed lands should be limited to less than 25%. Realistic chance for full restoration of water quality and improve 25-60% n/a Full Restoration quality of fish communities. Disturbed land percentage should be reduced and BMPs implemented. Restoration will be very expensive and probably will not achieve water quality conditions necessary to sustain healthy fish > 60% n/a Partial Restoration communities. Restoration opportunities must be critically evaluated to assure feasible positive outcomes.

The next step was to prioritize lakes within each of these management categories. DNR Fisheries identified high value fishery lakes, such as cisco refuge lakes. Ciscos (Coregonus artedi) can be an early indicator of eutrophication in a lake because they require cold hypolimnetic temperatures and high dissolved oxygen levels. These watersheds with low disturbance and high value fishery lakes are excellent candidates for priority protection measures, especially those that are related to forestry and minimizing the effects of landscape disturbance. Forest stewardship planning, harvest coordination to reduce hydrology impacts and forest conservation easements are some potential tools that can protect these high value resources for the long term.

Sibley’s lakeshed is classified with having 19.1% of the watershed protected and 21.9% of the watershed disturbed (Figure 19). Therefore, this lakeshed should have a protection focus. Goals for the lake should be to limit any increase in disturbed land use. Figure 20 displays the upstream lakesheds that contribute water to the lakeshed of interest. All of the land and water area in this figure has the potential to contribute water to Sibley, whether through direct overland flow or through a creek or river. There are 7 lakesheds upstream of the Sibley lakeshed.

Percent of the Watershed Protected

0% 75% 100%

Sibley (19.1%)

Percent of the Watershed with Disturbed Land Cover

0% 25% 100%

Sibley (21.9%)

Figure 19. Sibley’s lakeshed percentage of Figure 20. Upstream lakesheds that contribute water watershed protected and disturbed. to the Sibley lakeshed. Color-coded based on management focus (Table 12).

RMB Environmental Laboratories, Inc. 17 of 21 2013 Sibley Status of the Fishery (DNR, as of 07/28/1997)

Sibley is a 418 acre lake located at Pequot Lakes in Crow Wing County. A city owned public access is present on the northeast shore of the lake. In 1997, there were 152 homes/cabins and one resort located along the 8.1 miles of shoreline. The lake has a maximum depth of 40 feet and about 61% of the surface area is less than fifteen feet deep. It is classified as a hardwater lake with moderate phosphorus fertility. Water clarity was somewhat below average for lakes in the area. Soils in water less than four feet deep were primarily sandy, with varying amounts of muck, gravel and rubble sized (3-10") rock present, as well.

The aquatic plant community was fairly diverse. Emergent species help control nutrients in the lake. Plants like bulrush provide shorelines with some protection from wave caused erosion. They also enhance the quality of spawning habitat for bass and panfish species. Wild rice can also enhance spawning habitat for northern pike. Submerged and floating leafed species provide important cover and food sources for a wide variety of aquatic life.

A fisheries lake survey was conducted in 1997. A variety of sampling gear was used to sample fish populations. When compared to similar type lakes, the catch rate for black crappie was in the "high" category. Catches of rock bass, brown bullhead, yellow bullhead and bowfin (dogfish) were in the "low" category. Species present in "average numbers included northern pike, largemouth bass, bluegill, pumpkinseed, yellow perch and white sucker.

Past northern pike catch rates generally have ranged from "low" to "average," where the 1997 catch fell. Pike were 16-35 inches long, averaging 23 inches and 3.7 lbs. in size. Growth was "good." The 1993 year class was most abundant of the six year classes sampled. Walleye fingerlings were stocked by the lake association in 1991 and 1993. Walleyes were sampled in "low" numbers 1980, '85 and '90, but were not sampled in the '97 netting.

Largemouth bass were caught in "average" numbers in '97. Spring electrofishing was also done to sample bass. Spring sampled bass ranged from 5-17 inches long, averaged eleven inches long and represented five age classes. Growth was "good." Young bass were common in shoreline seine hauls done in early August.

Bluegills were caught in "average" numbers, similar to the '90 catch. Five age classes were sampled, the most abundant being from 1994. Young bluegills were abundant in shoreline seine hauls. Bluegills grew slowly, but about 7%, measured from trap nets, were at least 7.0 inches long; similar to a value of 8% in the 1990 netting.

Black crappies were in the "high" abundance category in 1997. Past catches ranged from "average" to "high." The '94 year class was the most abundant of the three age classes sampled. Young crappies were common in shoreline seine hauls. Crappie growth bordered on "slow."

Yellow perch and white suckers are important forage species for gamefish. Both were caught in "average" numbers in '97. Bullheads have typically been caught in "average" numbers in past nettings. Both brown and yellow bullheads were caught in "low" numbers in '97. Common carp are present in the Gull Chain. They were sampled in "low" numbers in Sibley Lake in 1990, but were not sampled in the 1997 netting.

See the link below for specific information on gillnet surveys, stocking information, and fish consumption guidelines. http://www.dnr.state.mn.us/lakefind/showreport.html?downum=18040400

RMB Environmental Laboratories, Inc. 18 of 21 2013 Sibley Key Findings / Recommendations

Monitoring Recommendations Transparency monitoring at sites 201-204 should be continued annually. It is important to continue transparency monitoring weekly or at least bimonthly every year to enable year-to-year comparisons and trend analyses. Total Phosphorus and chlorophyll a monitoring should continue at site 201, as the budget allows, to track trends in water quality.

Because of the intermediate depth of Sibley Lake and the phosphorus loading and algae blooms occurring, it would be helpful to monitor for internal loading. To confirm if internal loading is occurring, hypolimnion water samples (water samples taken 1 foot above the lake’s bottom) and corresponding dissolved oxygen profiles could be monitored for a summer or two.

It may be helpful to monitor the inlets to the lake to determine phosphorus loading from the watershed.

Overall Summary Sibley is a eutrophic lake (TSI = 56) with evidence of a declining trend in transparency. The total phosphorus, chlorophyll a and transparency ranges are poorer than the ecoregion ranges. Thirteeen percent (13%) of the lakeshed is public land and most of the private land use is categorized as forested uplands (25.1%) (Table 11). This land use category is generally good for water quality. When considering the MN DNR water quality modeling, it is concerning that the combined disturbed land uses make up 21.9% of the lakeshed (Figure 19). The threshold where water quality tends to decline is 25%.

Common carp are present in the Gull Chain. They were sampled in "low" numbers in Sibley Lake in 1990, but were not sampled in the 1997 netting.

Sibley Lake exceeds the Minnesota Pollution Control Agency’s Impaired Waters Standards, and is being considered for an impairment listing in 2014. If the lake is classified as impaired, a Total Maximum Daily Load Study will be conducted to determine the phosphorus sources to the lake and where they can be reduced.

Priority Impacts to the Lake The management focus for Sibley Lake should be to restore the water quality. Restoration efforts should be focused on managing and/or decreasing the impact caused by additional development, and impervious surface area. According to the DNR fisheries report “in 1997, there were 152 homes/cabins and one resort located along the 8.1 miles of shoreline.” Additional development within the first and second tier will have the greatest impact to the lake. It should also be noted that the City of Pequot Lakes is located within the lakeshed and the population is expected to increase by nearly 35% within the next 20-25 years causing increased develpoment.

Sibley Lake also has a large drainage area consisting of 7 upstream lakesheds. Many of these lakesheds are more disturbed than the Sibley lakeshed.

The chlorophyll a data show that Sibley Lake experiences nuisance algae blooms annually in late summer. This could be due to internal loading. Internal loading is when the phosphorus that is in the lake sediment re-suspends into the water column, feeding algae and plants. Phosphorus re- suspends when large boat motors churn up the sediment, and when the lake has a few calm days which allows it to loosely stratify, and then windy days, which mixes the water back up.

RMB Environmental Laboratories, Inc. 19 of 21 2013 Sibley The City of Pequot Lakes sits on the east side of Sibley Lake. It is important to implement good stormwater mitigation practices so that runoff from the impervious surface in the city does not run into Sibley Lake.

Best Management Practices Recommendations The management focus for Sibley Lake should be to restore the water quality and the lakeshed. Restoration efforts should be focused on managing and/or decreasing the impact caused by additional development, and impervious surface area. Project ideas include protecting land with conservation easements, enforcing county shoreline ordinances, smart development, shoreline restoration, rain gardens, and septic system maintenance.

Much of the shoreline around Sibley Lake is heavily forested close to the shoreline. Maintaining forested land cover along the shoreline is very important, especially along the eastern side of the lake to help filter and prevent additional runoff from the City of Pequot Lakes. When surface runoff flows through native vegetation, which has a much more robust root system than turf grass, and infiltrates into the soil it acts as a filter, slowing down and removing potential containments in the water.

According to the DNR fisheries report, “The aquatic plant community was fairly diverse. Emergent species help control nutrients in the lake. Plants like bulrush provide shorelines with some protection from wave caused erosion.” It is important for property owners along the lake to limit vegetation removal to a minimum along there shorelines.

There are some large undeveloped parcels on the south end of the lake that would be good candidates for conservation easements or wildlife management areas. The shoreline in that location is ringed with wetlands, and is most likely good quality fish and wildlife habitat.

Project Implementation The best management practices above can be implemented by a variety of entities. Some possibilities are listed below.

Individual property owners  Shoreline restoration  Rain gardens  Aquatic plant bed protection (only remove a small area for swimming)

Lake Associations  Lake condition monitoring  Internal loading monitoring  Stream inlet monitoring  Ground truthing – visual inspection upstream on stream inlets  Shoreline inventory study by a consultant

Soil and Water Conservation District (SWCD) & Natural Resources Conservation Service (NRCS)  Shoreline restoration  Stream buffers  Work with farmers to o Restore wetlands o Implement conservation farming practices o Land retirement programs such as Conservation Reserve Program

RMB Environmental Laboratories, Inc. 20 of 21 2013 Sibley Future Studies Future studies that would better pinpoint the impacts on the lake include a shoreline inventory, monitoring stream inlets, monitoring for internal loading, and a watershed flow analysis. The shoreline inventory would consist of driving around the lake and rating each parcel as to how much of the frontage has a vegetative buffer.

To determine the phosphorus loading from the watershed, the inlets could be monitored during baseline and peak flow events (spring thaw and heavy rains). The inlets could also be ground- truthed, which entails walking them to look for erosion and insufficient vegetative buffers.

Monitoring for internal loading involves collecting hypolimnion water samples (water samples taken 1 foot above the lake’s bottom) and corresponding dissolved oxygen profiles.

A watershed flow analysis would be done using GIS software to see the areas of heaviest runoff into the lake. This analysis would also help where stormwater mitigation, rain gardens and shoreline restoration would have the most positive impact on the lake.

County-wide Recommendation In order to better manage the impact of septic systems on lake water quality, it is recommended that the county implement a lake-wide septic inspection program. In a program such as this, the county would focus on one to three lakes a year, pull septic system records on those lakes, and require old systems to be inspected. This program can rotate through the county doing a few lakes each year.

Since conversion of small cabins to large lake homes could be a future issue, strengthening county shoreline ordinances such as set-backs, impervious surface limits and shoreline alteration (installation of retaining walls and removing trees) will help to protect water quality.

Organizational contacts and reference sites Sibley Association http://www.minnesotawaters.org/group/sibley

322 Laurel Street, Suite 14, Brainerd, MN 56401 Crow Wing County Land Services 218-824-1128 Department http://crowwing.us/index.aspx?nid=211 322 Laurel Street, Suite 13, Brainerd, MN 56401 Crow Wing Soil and Water (218) 828-6197 Conservation District http://www2.co.crow-wing.mn.us/swcd/ 1601 Minnesota Drive, Brainerd, MN 56401 DNR Fisheries Office (218) 828-2550 http://www.dnr.state.mn.us/lakefind/index.html 7678 College Road, Suite 105, Baxter, MN 56425 Regional Minnesota Pollution (218) 828-2492 Control Agency Office http://www.pca.state.mn.us 1601 Minnesota Drive, Brainerd, MN 56401 Regional Board of Soil and Water (218) 828-2383 Resources Office http://www.bwsr.state.mn.us

RMB Environmental Laboratories, Inc. 21 of 21 2013 Sibley