| Understanding the Factors
Affecting Water Quality in the Togus Pond Watershed |
| Colby Environmental Assessment Team | |
| Colby College, Biology Department | |
| December 9, 2004 |
| Presentation Overview |
| Introduction | |||
| Water Quality | |||
| Land Use | |||
| GIS Models | |||
| *Intermission* | |||
| Development | |||
| Phosphorus Budget | |||
| Remediation | |||
| Recommendations | |||
| Summary & Questions | |||
| An Introduction to our Study
of Togus Pond |
| Andrew Drummond |
| Background Overview |
| Study Objectives | |
| Values of Lakes | |
| Characteristics | |
| Study Objectives |
| Water Quality | |
| Land Use Analysis | |
| Predict Future Trends | |
| Recommendations |
| Value of Maine Lakes |
| Recreation | |
| Economic | |
| Biological |
| Lake Characteristics |
| Location | ||
| Kennebec County | ||
| Augusta | ||
| Elevation | ||
| 181ft | ||
| Depth | ||
| Average 17.8ft | ||
| Watershed | ||
| 4.76 mi2 | ||
| Includes Dam Pond | ||
| Lake Formation |
| Glacial Formation | ||
| Laurentide ice sheet | ||
| SSE movement | ||
| Damming | ||
| Series of Damming events | ||
| Evidence in stump fields and gravel boundaries | ||
| Land Use History |
| Maine | ||
| Agriculture | ||
| Reverting Forest | ||
| Togus Pond | ||
| Forest | ||
| Development | ||
| Water Quality |
| Algal Blooms | ||
| Limited by Phosphorus | ||
| Implications | ||
| Maine Lakes | ||
| 38 lakes commonly | ||
| bloom in Maine | ||
| Attempted Remediation | ||
| Copper Sulfate | ||
| Hypolimnetic Aeration | ||
| Lake Turnover |
| "Eutrophication" |
| Eutrophication |
| Aquatic Flora & Fauna |
| Aquatic Plants | ||
| Importance | ||
| Invasives | ||
| Aquatic Flora and Fauna |
| Fish | ||
| Warmwater Fishery | ||
| Stocking | ||
| An Assessment of Water Quality |
| Natalie Maida |
| Water Analysis Overview |
| Sample Site Locations | |
| Physical Measurements | |
| Chemical Tests | |
| Biological Tests |
| Sample Sites |
| Characterization Sites: | |
| 1, 2, 3 | |
| Spot Sites: 4, 5, 6, 7, 8, 9 (culvert) | |
| Tests performed through the summer and early fall | |
| Analyses performed on site, in the Colby Environmental Analysis Center, or by Northeast Laboratory |
| Physical Tests |
| Dissolved Oxygen | |
| Temperature | |
| Transparency | |
| Turbidity | |
| Color | |
| Conductivity |
Dissolved Oxygen |
| Historical DO |
| Anoxic Volume of the Lake |
| Togus Pond lake water is anoxic below 8 m. | |
| 12% of the lake volume is anoxic |
Temperature |
| Transparency |
| Historical Transparency |
| Other Physical Tests |
| Turbidity- mean 4 NTU | |
| Color- mean 45 SPU | |
| Conductivity- mean 58 mmhos/cm | |
| Slide 26 |
| Chemical Tests |
| pH | |
| Hardness | |
| Nitrates | |
| Alkalinity | |
| Ammonium | |
| Phosphorus |
pH |
| Hardness |
| Other Chemical Tests |
| Nitrates- mean 0.9 ppm | |
| Alkalinity- mean 18 ppm | |
| Ammonium- mean 0.08 ppm | |
| Phosphorus- mean 28 ppb | |
| Slide 31 |
Biological Tests Chlorophyll-a |
| Chlorophyll-a |
| Fecal Coliform |
| Fecal coliform was tested at 3 sites across the lake and all results measured 0 CFU/100mL |
| Water Analysis Conclusions |
| Color: mean 44 SPU | |
| Conductivity: mean 58 µmhos/cm | |
| Nitrates: mean 0.95 ppm | |
| Hardness: mean 22mg/L | |
| High Values Found |
| Land Use Analysis of the Togus Pond Watershed |
| Tim Lancaster |
| Land Use Assessment Overview |
| Methods of land use classification (GIS) | |
| Land use categories | |
| Water quality impacts of land use types | |
| Land use changes in Togus Pond watershed |
| Land Use Assessment |
| Land use types have varying effects on lake water quality | |
| Assessment of land use patterns and historical trends is essential to evaluate ecosystem health |
| Geographic Information System (GIS) |
| GIS: a computer system used for displaying and manipulating geographic data that shares a common coordinate system |
| GIS Land Use Analysis |
| Each variable is displayed as a ÒlayerÓ | |
| Objects in a layer can be represented by points, lines, or areas (polygons) | |
| Layers can be overlain and manipulated |
| Aerial Photography |
| Georeferencing |
| Togus Pond Watershed 1954 |
| Togus Pond Watershed 2002 |
| Land Use Classifications |
| Cropland | |
| Hayland | |
| Pasture | |
| Residential | |
| Commercial/Municipal | |
| Mature Forest | |
| Transitional Forest | |
| Wetland | |
| Old Field | |
| Cleared | |
| Residential and Commercial/Municipal |
| Cleared and Old Field |
| Agriculture and Wetland |
| Drawing Polygons |
| Digitizing Land Use Types |
| Land Use Maps |
| Water Quality Impacts |
| Optimal land use type for erosion control | |
| Vegetation provides a physical barrier to erosion and a sink for nutrients | |
| 63% of the watershed |
| Water Quality Impacts |
| Transitional zone between aquatic and terrestrial ecosystems | |
| Act as a filter by removing sediments and pollutants from runoff water | |
| Act as nutrient sinks or sources | |
| 2% of the watershed |
| Water Quality Impacts |
| Logging leaves exposed soil and debris that is easily eroded | |
| Early successional vegetation does little to control runoff | |
| 3% of the watershed |
| Water Quality Impacts |
| Exposed soil erodes quickly | |
| Chemical fertilizers are high in phosphorus | |
| Often heavy pesticide inputs | |
| <1% of the watershed |
| Water Quality Impacts |
| Sloped lawns and impervious surfaces promote runoff | |
| Inadequate septic systems contribute nutrients | |
| Residential = 5% | |
| Commercial/Municipal = 2% |
| Water Quality Impacts |
| Soil erodes quickly from dirt roads and road shoulders | |
| Paved roads represent impervious surfaces, and increase runoff and pollutant inputs | |
| 1.5% of the watershed |
| Land Use Change: 1954 to 2002 |
| Regeneration of forest from agricultural and other disturbed lands | |
| Increasing development primarily from forested land, concentrated on the lake shoreline | |
| GIS Modeling |
| Carolyn Hunt |
| Erosion Potential Model |
| Slide 61 |
| Using the Erosion Potential Model |
| A tool for land use planning | |
| Finds potential sources of phosphorus | |
| Targets areas for mitigation | |
| Septic Suitability Model |
| Slide 64 |
| Using the Septic Suitability Model |
| New septic systems | |
| Monitoring old septic systems | |
| Potential problem areas |