| Land Use Patterns in Relation to Lake Water Quality in the Lake George and Oaks Pond Watersheds |
| Problems in Environmental Science | |
| Biology 493 | |
| Colby College | |
| Waterville, ME |
| Outline of Presentation |
| SECTION 1 | ||
| Characteristics of Lake George and Oaks Pond | ||
| Watershed Land Use | ||
| Geographic Information Systems (GIS) | ||
| Development | ||
| INTERMISSION | ||
| SECTION 2 | ||
| Lake George Regional Park | ||
| Water Chemistry | ||
| Phosphorus Loading Model & Future Projections | ||
| Summary & Recommendations | ||
| QUESTIONS & ANSWERS | ||
| General Characteristics of Lake George and Oaks Pond |
| Kirsten Ness |
| Objectives of the Study |
| Determine the current water quality of Lake George and Oaks Pond | |
| Identify possible inputs of nutrients and pollutants | |
| Suggest ways to maintain quality of the lakes and improve problematic areas |
| Methods |
| Water Quality Assessment | ||
| Data Acquisition | ||
| Water Chemistry | ||
| Watershed Assessment | ||
| Land Use | ||
| GIS | ||
| Development | ||
| Definition of a Watershed |
| Area of land that contributes runoff to a body of water | |
| Watershed boundaries obtained from MDEP |
| Lake Stratification |
| Layers of lakes | ||
| Epilimnion | ||
| Thermocline | ||
| Hypolimnion | ||
| Dimictic lakes | ||
| Overturn occurs twice each year | ||
| Lake George |
| Area = 304 acres | |
| Maximum depth = 68 ft | |
| Mean depth = 24 ft | |
| Deep basin | |
| Two major inlets | |
| One outlet |
| Oaks Pond |
| Area = 87 acres | |
| Maximum depth = 53 ft | |
| Mean depth = 25 ft | |
| Deep basin | |
| Two major inlets | |
| One outlet |
| Geology |
| Glacial formation of lakes | ||
| North / South orientation | ||
| Dominant soil series | ||
| Thorndike | ||
| Plaisted | ||
| Trophic State |
| Oligotrophic | ||
| Low nutrient levels | ||
| Low productivity | ||
| Young | ||
| Eutrophic | ||
| High nutrient levels | ||
| High productivity | ||
| Mature | ||
| Mesotrophic | ||
| Moderate nutrient levels | ||
| Moderate productivity | ||
| Cultural Eutrophication |
| Accelerated eutrophication due to human activity | |
| Increased levels of nutrients | |
| Phosphorus and nitrogen |
| Macrophytes |
| Native plant species | ||
| Arrowhead | ||
| Coontail | ||
| Elodea | ||
| Northern pipewort | ||
| Pickerel weed | ||
| Pond lilies | ||
| Watershield | ||
| Macrophytes |
| Invasive plant species | ||
| Variable leaf milfoil | ||
| Eurasian milfoil | ||
| Parrot feather | ||
| Fisheries |
| Lake George and Oaks Pond | ||
| Warm water fishery | ||
| Cold water fishery | ||
| Stocking | ||
| Land Use Patterns |
| Creation of land use maps | |
| Land use categories | |
| Results | |
| Trends over time |
| Land Use Assessment |
| Land use types have varying effects on lake water quality | |
| Different vegetation cover influences surface runoff and erosion | |
| Essential to evaluate the patterns and trends in order to evaluate ecosystem health |
| Steps in Creating the Land Use Maps |
| Obtain aerial photographs | ||
| 1955 from James W. Sewall Company | ||
| 1997 from USGS | ||
| Scan images and align in GIS | ||
| Determine land use categories | ||
| Classify areas using GIS | ||
| Aerial Photograph (1955) |
| Land Use Categories |
| Natural Uses | |
| Wetlands | |
| Mature Forest | |
| Transitional Forest | |
| Regenerating Forest | |
| Reverting Land | |
| Development Uses | |
| Commercial | |
| Agricultural | |
| Cleared | |
| Residential | |
| Roads | |
| Wetlands |
| Transitional areas between terrestrial and aquatic ecosystems | |
| Serve as sources and sinks for phosphorus | |
| Less than 5% of watersheds |
| Forests |
| Positive benefit on water quality | |
| Buffers against erosion and allows nutrients time to bind to soil | |
| Regenerating Land |
| Early successional stage which follows logging | |
| Even stand of vegetation |
| Reverting Land |
| Filling in of an old field with pioneer species | |
| Patchy forest cover | |
| Represents a small percentage | |
| Residential and Commercial Lands |
| Shoreline and non-shoreline | |
| LGRP, businesses, gravel pits, and Eaton Mountain ski slope | |
| Increases in the amount of impervious surfaces increases runoff | |
| All represent small percentages | |
| Agricultural Land |
| One of leading sources of lake pollution | |
| Currently a small percentage of land uses |
| Roads |
| Roads fragment ecosystem | |
| Result in large areas of impervious services | |
| Represent approximately one percent of total areas |
| Cleared Areas |
| Includes selection cuts, logging roads, and skidder trails | |
| Clearcutting can increase amount of runoff by 45% |
| Slide 29 |
| Land Use Patterns in 1955 and 1997 |
| Land Use Summary |
| Decreased agriculture | |
| Increased forested areas | |
| Increased shoreline residential areas | |
| Careful monitoring of logging and development in future |
| Geographic Information Systems (GIS) |
| Michael J. Rogalus III |
| What is GIS? |
| Slide 34 |
| Slide 35 |
| Slide 36 |
| Slide 37 |
| Slide 38 |
| Slide 39 |
| Models |
| Erosion Potential Model | ||
| Logging Suitability Model | ||
| Development Suitability Model | ||
| Erosion Potential Model |
| Erosion Potential Model |
| Erosion Potential Model |
| Erosion Potential Model |
| Logging Suitability Model |
| Logging Suitability Model |
| Logging Suitability Model |
| Logging Suitability Model |
| Development Suitability Model |
| Development Suitability Model |
| Development Suitability Model |
| Development Suitability Model |
| GIS Summary |
| Development Deandra Brassard |
| Shoreland Zoning | |
| Residential Survey | |
| Buffer Strip Survey | |
| Septic Systems | |
| Road Survey |
| Shoreland Zoning |
| Shoreland Zoning Ordinance | ||
| Encourage responsible development | ||
| Protect water quality | ||
| Limit erosion | ||
| Conserve wildlife and vegetation | ||
| Shoreland Zone = land within 250 ft of the normal high water mark of a lake | ||
| Shoreland Zoning Regulations |
| 100 ft minimum setback from the shoreline | ||
| Additional regulations | ||
| Lot size | ||
| Septic system placement | ||
| Expansion of existing buildings | ||
| Non-Conformance |
| Many homes do not conform to the regulations | |
| Important to reduce the number of | |
| non-conformities over time |
| Residential Survey |
| Negative effects of residential land | |||
| Added nutrients | |||
| Fertilizers and pesticides | |||
| Household waste | |||
| Septic systems | |||
| Increased run off due to impervious surfaces | |||
| Driveways | |||
| Roof tops | |||
| House counts | |||
| Shoreline versus non-shoreline | |||
| Seasonal versus year round | |||
| Residential Survey Results |
| Lake George (56 houses) | ||
| 61% shoreline | ||
| 39% non-shoreline | ||
| 55% seasonal | ||
| 45% year round | ||
| Oaks Pond (141 houses) | ||
| 38% shoreline | ||
| 62% non-shoreline | ||
| 33% seasonal | ||
| 67% year round | ||
| Residential Survey |
| Conversion of homes from seasonal to | ||
| year round | ||
| Shoreline development | ||
| Lake George | ||
| Oaks Pond | ||
| Residents should practice good buffer management techniques | ||
| Buffer Strips |
| Minimize surface runoff | |
| Help prevent erosion | |
| Absorb nutrients and pollutants | |
| A buffer should consist of four layers: | |
| trees, shrubs, groundcover, and a duff layer |
| Buffer Strip Survey |
| Percent lakeshore buffer coverage | |
| Buffer depth from shoreline | |
| Slope between house and shore | |
| Buffer composition |
| Buffer Strip Survey Results |
| Slide 64 |
| Septic Systems |
| Store and treat fecal waste | ||
| Improper maintenance | ||
| Increased nutrient loading | ||
| Contamination of lake water | ||
| Regulations | ||
| Setback, volume, and location | ||
| Inefficient systems are present in the watershed | ||
| Septic Systems |
| Many shoreline systems were not designed to handle current use | |
| New and replacement systems must comply with strict regulations | |
| Voluntary upgrades may improve lake water quality |
| Road Survey |
| Impervious surfaces | ||
| Direct path for runoff | ||
| Deposit nutrients and contaminants into lakes | ||
| In some watersheds, up to 80% of phosphorus loading is attributed to roads | ||
| Non-detailed survey paved roads | ||
| Detailed survey camp roads | ||
| Road Survey |
| Road survey factors | ||
| Surface cover, ditches, culverts, water diversions, erosion potential, and total area | ||
| Road classification | ||
| Severe risk, high risk, risk, acceptable, and ideal | ||
| Road Survey |
| Effective culvert | |
| Ineffective culvert |
| Road Survey Results |
| Road Survey Results |
| Development Summary |
| Development increases | ||
| Number of impervious surfaces | ||
| Area of cleared land | ||
| Number of septic systems | ||
| Amount of waste being generated | ||
| Maintaining healthy lakes | ||
| Careful future planning | ||
| Environmentally friendly maintenance techniques | ||
| INTERMISSION |