| Slide 1 |
| Presentation Overview |
| Introduction | |
| Water Quality Analysis | |
| Land Use Analysis | |
| -Intermission- | |
| GIS Analysis and Models | |
| Development | |
| Recommendations | |
| Anna Sommo |
| Introduction | |
| Characteristics of Maine Lakes | |
| Threemile Pond Overview | |
| Study Objectives | |
| The Value of Maine Lakes |
| Recreational uses | |
| Economic value | |
| Property value |
| General Characteristics of Maine Lakes |
| 10,000 years old | |
| Lowland areas | |
| Northwest to Southeast orientation |
| Watershed Definition |
| The total area draining into a particular basin | |
| Begins at the highest points of land surrounding a basin |
| Geographical Perspective of Threemile Pond |
| China | |
| Vassalboro | |
| Windsor | |
| Augusta | |
| The History of Threemile Pond |
| Farmland and residential development | |
| Annual algae blooms since the first half of the 20th century | |
| MDEP considers lake water quality poor | |
| Aquatic Flora and Fauna |
| Aquatic plants | |
| Invasive Plants |
| Spread easily and rapidly | |
| Overwhelm ecosystems and fill in lakes |
| Eutrophication |
| Turnover |
| Threemile Pond is dimictic | |
| Stratification can lead to anoxic conditions | |
| Anoxic conditions cause phosphorus release | |
| P promotes algal growth |
| Study Objectives |
| Water Quality Analysis | |
| Land Use Assessment | |
| Future Trends |
| Water Quality |
| Bethany Craig |
| Overview |
| Sample site locations | |
| Physical measurements | |
| Chemical tests | |
| Sample Site Locations |
| 3 Characterization Sites | |
| 5 Spot Sites | |
| 4 Tributary Sites |
| Dissolved Oxygen |
| Concentration of oxygen in water column | |
| Anoxic levels in hypolimnion | |
| Dissolved Oxygen |
| August anoxic depths | |
| 46% of surface area of lake over anoxic water | |
| Implications for nutrient loading | |
| Implications for fisheries |
| Physical Measurements: Selected Results |
| Transparency | |
| Measures water clarity and suspended particulate matter | |
| Transparency < 4 m = eutrophic | |
| August mean=0.7 m | |
| September mean=2.9 m | |
| Turbidity | |
| Measures light scattered by suspended particulate matter | |
| Normal <50 NTUs | |
| August mean=23.6 NTUs | |
| September mean=1.62 NTUs | |
| Physical Measurements: Selected Results |
| True Color | |
| Measures natural dissolved organic acids | |
| Uncolored < 30 SPUs | |
| Maine average 27 SPUs | |
| September mean=14.2 SPUs | |
| Conductivity | |
| Measures ability of water to carry electrical current | |
| Normal: 20-40 mMHOs/cm | |
| September mean=48.2 mMHOs/cm |
| Chemical Tests: Selected Results |
| pH | |
| Measures relative acidity of water | |
| Neutral= pH of 7 | |
| September mean=7.1 | |
| Alkalinity | |
| Measures ability of water to buffer against pH changes | |
| September mean=42.5 | |
| Higher than average Maine lakes |
| Chemical Tests: Selected Results |
| Hardness | |
| Measures concentration of Magnesium and Calcium ions | |
| Soft water 0 to 60 mg/L | |
| September mean= 4.04 mg/L | |
| Soft water implications |
| Nutrient Loading |
| Plants need variety of nutrients to grow | ||
| Nitrogen and Phosphorus most important nutrients in aquatic systems | ||
| Eutrophication | ||
| Natural | ||
| Cultural | ||
| Nitrates and Nitrites |
| Measures total amount of nitrates and nitrites in water | ||
| Sources | ||
| Fertilizers | ||
| Septic tanks and animal waste | ||
| Normal < 1 ppm | ||
| September mean =0.06 ppm | ||
| Phosphorus |
| Tom Rogers |
| Phosphorus |
| Why phosphorus is important to study | |
| Historical phosphorus data for Threemile Pond | |
| Current phosphorus data for Threemile Pond | |
| How Threemile Pond compares with other Maine lakes | |
| Water budget |
| Phosphorus |
| Necessary for aquatic plant growth | |
| Found in all soils and organic matter and on all surfaces | |
| Carried in ground water and in streams | |
| Used in fertilizers | |
| Found in septic systems |
| Phosphorus Deposition |
| Primary cause of algal blooms in Maine lakes | |
| Deposited through surface water runoff and in streams | |
| Lakes turn green in color and unappealing in taste and odor | |
| Decreases recreational value of lakes and property value within watershed |
| Historical Total Phosphorus- Threemile Pond |
| August 2003 Phosphorus Readings |
| Phosphorus for Surrounding Lakes in Recent Years |
| September 2003 Phosphorus Readings |
| Tributary Water Quality |
| Major input to lakes | |
| Quality of water entering and leaving lake | |
| Sources or sinks for nutrients | |
| Flow rate changes seasonally |
| Tributary Data for Sept. 2003 |
| Sites 9 and 10 -Seward Mills Brook --Outlet | |
| Site 11 -Unnamed stream from wetlands --Inlet | |
| Site 12 -Barton Brook from Threecornered Pond & Mud Pond --Inlet |
| Water Budget -Flushing Rate |
| Rate at which a lake replenishes water | |
| Given for lakes of similar area and depth to Threemile Pond |
| Land Use Kelly Welch |
| Overview |
| Introduction to land use | |
| Historical land use trends | |
| Land use categories | |
| Results | |
| Summary of findings | |
| Watershed Land Use |
| Examined land use changes between 1956 and 1998 | ||
| Why examine land use changes? | ||
| Effects of land use types | ||
| Historic trends | ||
| Identify potential sources of pollution | ||
| Regional Land Use Trends |
| Decline in agriculture throughout New England | ||
| Maine State trends | ||
| 90% forested | ||
| 3% agriculture | ||
| 2% urban | ||
| 5% other (wetlands, residential, transportation uses) | ||
| Maps |
| Used digital orthophoto quadrangles downloaded from the Maine Office of GIS for 1998 | |
| Aerial photos for 1956 | |
| Computer program ArcMapTM |
| Methods |
| Polygons drawn | ||
| Color codes to distinguish between land use categories | ||
| Calculated the cumulative area | ||
| Comparison made between 1956 and 1998 watersheds | ||
| Slide 42 |
| Land Use Classifications |
| Natural | ||
| Wetlands | ||
| Forest types | ||
| reverting | ||
| transitional | ||
| mature | ||
| Developed | ||
| Cleared land | ||
| Agriculture | ||
| cropland | ||
| pasture | ||
| Commercial and municipal | ||
| Residential | ||
| Wetlands |
| Transitional zone between terrestrial and aquatic ecosystems | |
| Includes all forms of freshwater wetlands |
| Forests |
| Undeveloped land | |
| Different stages of succession | |
| Reverting- canopy < 50% | |
| Transitional- canopy >50% | |
| Mature- closed, continuous canopy | |
| Slide 46 |
| Cleared Land |
| Agricultural |
| Pasture- cleared land, no crop rows | |
| Cropland- exhibits even rows | |
| Commercial and municipal |
| Businesses and public facilities | |
| Concentrated in China at the north end of the lake | |
| Residential |
| Shoreline | |
| Non-shoreline |
| Patterns of Land Use in the
Threemile Pond Watershed |
| Percent of the watershed covered by each land use category |
| Land Use Summary |
| Decline in agricultural uses | |
| Residential development increased | |
| Wetlands remained constant | |
| Commercial and municipal uses increased | |
| Threemile Pond is similar to regional trends |
| Intermission |