| A Watershed Analysis of China Lake |
| Colby Environmental Assessment Team | |
| Department of Biology, Colby College | |
| Waterville, ME | |
| December 8, 2005 |
| Presentation Overview |
| Introduction | |
| Water Quality Analysis | |
| Geographic Information Systems | |
| Land Use Analysis | |
| Intermission | |
| Development | |
| Phosphorus Budget | |
| Lake Remediation | |
| Summary | |
| Study Objectives |
| Water Quality Analysis | |
| Land Use Analysis | |
| Development Surveys | |
| Future Projections | |
| Remediation Possibilities |
| Slide 4 |
| The Value of Maine Lakes |
| Intrinsic (Biodiversity, Beauty) | ||
| $6.7 Billion Annual Net Value | ||
| Commercial | ||
| Recreational | ||
| Drinking Water | ||
| China Lake |
| China Lake Formation |
| Laurentide Ice Sheet | |||
| Receded from Maine 10,000 years ago | |||
| Created southeasterly orientation | |||
| Basin composition | |||
| - Glaciomarine clay-silt | |||
| - Bedrock | |||
| - Glacial till | |||
| Nutrient poor | |||
| Predicts lakes to be oligotrophic | |||
| The Watershed |
| Watershed | ||
| A watershed is the total land area that contributes a flow of water to a particular basin | ||
| China Lake Watershed | ||
| 85.15 km2 | ||
| Includes sub-watershed of Evans Pond | ||
| Municipal Jurisdiction |
| China | ||
| 75.47 km2 | ||
| Jones Brook | ||
| Wetlands | ||
| Vassalboro | ||
| 7.68 km2 | ||
| Dam | ||
| Outlet Stream | ||
| Albion | ||
| 2.00 km2 | ||
| Historical Land Use |
| Agriculture | |
| Commercial | |
| Residential | |
| China Lake Dam Water Level |
| Dam is located in the Town of Vassalboro | |
| Dam was first constructed in 1800�s | |
| Raised to its current level in 1969 | |
| Elevation of spillway is 171.5 feet | |
| Fish Population of China Lake |
| Native Species | ||
| Largemouth Bass | ||
| Smallmouth Bass | ||
| Brown Bullhead | ||
| White Perch | ||
| Yellow Perch | ||
| Brown Trout | ||
| Chain Pickerel | ||
| Smelt | ||
| Manipulated Fish Species |
| Non Native Species | ||
| Black Bass | ||
| Black Crappie | ||
| Northern Pike | ||
| Alewife | ||
| Stocked Species | ||
| Brown Trout | ||
| Brook Trout | ||
| Invasive Species |
| Maine Lists Eleven Aquatic | ||
| Invasive Species | ||
| Infestations of Five | ||
| Species | ||
| None in China Lake | ||
| Boating Activity | ||
| Susceptibility | ||
| Hydrilla | ||
| Eurasian Water Milfoil | ||
| Variable-Leaf Milfoil | ||
| Natural Eutrophication |
| Eutrophication is the natural aging process of lakes | ||
| Lake Classifications | ||
| Oligotrophic | ||
| Mesotrophic | ||
| Eutrophic | ||
| Eutrophic Lakes |
| EPA classification of an lake as eutrophic requires these relative characteristics | ||
| Lower dissolved oxygen concentrations in hypolimnion | ||
| Higher nutrient content | ||
| Increased suspended matter | ||
| Increased turbidity | ||
| Increased phosphorous concentration in sediment | ||
| Cyanobacteria population | ||
| Anthropogenic Influence
on Eutrophication |
| Development of | |
| Watershed | |
| Point Sources | |
| Increased Runoff | |
| Non Point Sources |
| Stratification and Turnover |
| Stratification | ||
| Epilimnion | ||
| Thermocline | ||
| Hypolimnion | ||
| Seasonal Turnover | ||
| Dimictic Lakes | ||
| Algal Blooms |
| Anthropogenic | ||
| Influences | ||
| Algal Population | ||
| - 3 cyanobacteria | ||
| - 1 green alga | ||
| - 3 diatoms | ||
| Timing of blooms | ||
| Three distinct blooms | ||
| - Spring | ||
| - Late Summer | ||
| - Fall | ||
| Slide 20 |
| Sample Site Locations |
| China Lake Bathymetry |
| Water Quality Measurements |
| Physical Parameters | |
| Temperature | |
| Dissolved Oxygen | |
| Conductivity | |
| Transparency | |
| Turbidity | |
| Color | |
| Biological Parameter | |
| Chlorophyll-a | |
| Chemical Parameters | |
| pH | |
| Alkalinity | |
| Nitrates | |
| Total Phosphorus |
| Physical and Biological Parameters |
| Historic Temperature |
| Dissolved Oxygen Profile |
| Summary of Bloom Parameters |
| Summary of Bloom Parameters |
| Chemical Parameters |
| pH Profile |
| Alkalinity |
| Surface Nitrates |
| Nitrate Profile |
| Nitrates in Local Lakes |
| Total Phosphorus |
| Slide 36 |
| Historic Phosphorus |
| Nutrient Loading |
| Addition of nutrients into the lake | |
| Direct result of the combination of human activities and runoff | |
| Slide 39 |
| Geographic Information System |
| Geographic Information System (GIS) | |
| A computer system based on a common coordinate system designed to display, manipulate, and analyze geographic data |
| GIS Analysis |
| Geographic data displayed as a layer | |
| Can add, manipulate, or create new data, represented by points, lines, or area (polygons) |
| Uses of GIS Analysis |
| Surveying | ||
| Land Use Analysis | ||
| Modeling | ||
| Septic Suitability Model | ||
| Erosion Potential Model | ||
| Potential Erosion Impact Model | ||
| Land Use Analysis |
| Can find patterns in land use and development | ||
| Establishes rate of development for a given period | ||
| Can be used to predict future development | ||
| Land use patterns reflect changes in: | ||
| Erosion | ||
| Sediment Loading | ||
| Nutrient Loading | ||
| Land Use Analysis Methods |
| Determine period of study | |
| Compile and import images of China Lake watershed into GIS | |
| Determine and identify different land use types | |
| Following land use identifications, use GIS to designate areas of different land use | |
| Compute areas of each land use type | |
| Complete for both 1965 and 2003 surveys |
| China Lake Watershed 1965 |
| 18 large format aerial photographs | ||
| USDA | ||
| GIS coordinates system not yet incorporated | ||
| Georeferencing |
| Incorporation of the GIS Coordinate System with aerial photographs | |
| China Lake Watershed 2003 |
| 14 Digital Orthophoto Quadrangles (DOQ) | |||
| Downloaded from Maine Office of GIS | |||
| GIS coordinate system incorporated | |||
| No need to georeference | |||
| Land Use Classifications |
| Agriculture Land | |
| Commercial/Municipal Land | |
| Residential Land | |
| Reverting Land | |
| Forest | |
| Wetlands | |
| Lake/Ponds |
| Agricultural Land |
| Residential and Commercial/Municipal |
| Forest and Wetlands |
| Reverting Land |
| Creating Polygons |
| Designating land use types within GIS |
| Land Use Maps |
| Lake Quality Impacts: Agriculture |
| Fertilizers contribute high levels of phosphorus | |
| High erosion potential | |
| Increased runoff | |
| 14.1% of watershed land area in 2003 | |
| Down from 21.3% in 1965 | |
| Lake Quality Impacts: Forest |
| Low erosion and runoff | |
| High nutrient absorption | |
| 61.9% of watershed land area in 2003 | |
| Up from 59.5% in 1965 | |
| Lake Quality Impacts: Reverting |
| Marginal runoff and erosion control | |
| Residual phosphorus from previous agricultural land use | |
| 3.3% of watershed land area in 2003 | |
| Down from 9.3% in 1965 |
| Lake Quality Impacts: Wetlands |
| Absorbs nutrients that would otherwise run into the lake | |
| 9.5% of watershed land area in 2003 | |
| Up from 7.2% in 1965 |
| Lake Quality Impacts: Residential |
| High levels of impervious surfaces | |
| Pollutants from household chemicals and neglected septic systems | |
| 8.1% of watershed land area in 2003 | |
| Up from 2.3% in 1965 | |
| Lake Quality Impacts: Commercial/Municipal |
| Large impervious surfaces | |
| High levels of traffic | |
| Highly used septic systems | |
| 1.9% of watershed land area in 2003 | |
| Up from 0.4% in 1965 |
| Lake Quality Impacts: Roads |
| Impervious surface can channel water and nutrients into the lake | ||
| Paved and camp roads | ||
| 1.1% of watershed land area in 2005 | ||
| Map of Land Use Change |
| 1965-2003 | ||
| Based on grouping of land use types | ||
| Developed | ||
| Undeveloped | ||
| Land Use Summary |
| Land use trends | ||
| Decreases in agricultural land between 1965 and 2003 | ||
| Increases in residential land | ||
| Land use changes are relevant to nutrient loading | ||
| GIS modeling | ||
| Phosphorus budget | ||
| GIS Models |
| Andrew Johnson |
| Slide 65 |
| Septic Suitability |
| Slope Data |
| Slope derived from elevation model | |
| Slopes range from 0 to 59% | |
| Slopes scaled to a 1 - 9 range |
| Soil Septic Suitability |
| Weighted Overlay |
| Septic Suitability |
| Erosion Potential |
| Soil K-factor Map |
| Land Use Erosion Risk Map |
| Erosion risk values were chosen and applied to the different land use types | |
| Values ranged from 1 to 9 |
| Weighted Overlay |
| Potential Impact of Erosion |
| Proximity to Lake |
| Proximity to Streams |
| Weighted Overlay |
| Potential Impact of Erosion |
| Slide 80 |