activities take place in areas that were formerly forests, barrens, or 

 wetlands . 



Soil Erosion 



High surface runoff from cleared agricultural land causes excessive erosion of 

 soil. Between 2000 and 7350 tons (1815 and 6670 t) of soil are eroded away 

 annually in each region of coastal Maine (U.S. Soil Conservation Service 

 1979). The most important factors causing soil erosion in Maine have been 

 identified as steepness and length of slope, poor rotation cycle, and 

 uphill/downhill cultivation (U.S. Soil Conservation 1979). Soil-type is 

 another contributing factor. Tolerable soil loss for Maine's soil, as 

 established by the Soil Conservation Service, is 3 tons (2.7 t)/acre/year . 

 Locally severe soil erosion problems are, however, possible at lower levels 

 than this. Knox and Lincoln Counties (regions 3 and 4) have the highest 

 average soil loss (12.8 tons; 12 t/acre/year) . Waldo County (region 4) 

 follows with 5.6 tons (5 t)/acre/year . Sagadahoc County (region 2) has an 

 average soil loss of 2.4 tons (2.1 t)/acre/year which is below tolerable 

 levels. Approximately half of the 2900 acres (810 ha) of cropland surveyed 

 for soil loss in the characterization area were above tolerable levels. 



Eroded soil is deposited in streams, lakes, ponds, upland fields, and flood 

 plains. Two bodies of water in region 1 were found to receive approximately 

 30% of the total sediment that is in motion in their respective watersheds 

 during the year. Sediment carries pesticides and nutrients and excessive 

 sediment reduces water quality. 



Excessive sediment deposits and turbidity can reduce the capacity of a pond or 

 stream to produce fish and other desirable aquatic organisms. Fish habitat 

 can be destroyed and juvenile fish can be killed by silt-laden water. Fine 

 sediment may clog the gills of finfish and other aquatic organisms. Turbid 

 water may affect the productivity of aquatic plants by reducing light 

 penetration. Silt deposits on the leaves of submerged aquatics have a similar 

 effect. Reducing the aquatic invertebrate species and aquatic vegetation 

 limits the primary foods and important cover of juvenile salmon, trout, and 

 bass. Over long periods of time fish become fewer and smaller. 



Nutrient Runoff 



Excessive runoff from animal manure and fertilizer pollutes the waters of 

 coastal Maine (U. S. Soil Conservation Service 1979). The most widespread 

 pollution of this kind in Maine is caused by improper storage of manure. 



No specific data are available on the amount of manure spread on fields or the 

 number of improper storage facilities in the characterization area. Waldo 

 County (regions 3 and 4) has the highest number of animal units (30,100) and, 

 consequently, the highest production of manure (350,000 tons; 372 t/year). 

 [_\n animal unit is a standardized measure of livestock biomass and is 

 equivalent to 1000 lb (400 kg), live weight.] Following in decreasing order 

 of production are Cumberland (9250 AU in region 1), Knox and Lincoln (combined 

 5260 AU in regions 3 and 4), Sagadahoc (2010 AU in region 2), Hancock (1583 Au 

 in regions 4 and 5), and Washington (1325 AU in regions 5 and 6) Counties. 

 The greatest number of large farms (>1000 AU) is located in the Androscoggin 

 and Kennebec watersheds. Most are within 30 miles of the coastal zone. A 



3-8 



