Spawning populations of the American shad and sturgeon species also have been 

 greatly reduced. Atlantic salmon, whose runs were greatly reduced, are now 

 beginning to respond to intensive restoration efforts. Anadromous alewives 

 and rainbow smelt, although generally abundant, have experienced many local 

 disruptions. Migrations of nonanadromous resident fishes, such as trout and 

 landlocked salmon, probably also have been disrupted, although this situation 

 has received relatively little attention. 



Dams are present at the outlets of many lakes in the coastal zone (a partial 

 list is given in table 3 in the appendix to chapter 7 , "The Lacustrine 

 System"). With few exceptions, these dams have been built on natural lakes 

 and have raised the maximum water levels. These dams serve, or once served, 

 purposes including ice production, powering of mills at outlets, controlled 

 release of water for recreation, and electrical power production. Water-level 

 manipulation at dam sites may affect lacustrine biota and fish spawning areas. 

 Potential adverse effects of hydroelectric dams exist at Branch Lake (region 

 5) and Toddy Pond (region 4). Numerous dams at lake outlets have fallen into 

 disrepair because the original purposes of the dams no longer exist and laws 

 are inadequate to enforce maintenance. These and the still-functional dams 

 are matters of State and local controversy. Conflicts in relation to desired 

 water levels exist between dam operators, boatsmen, fishermen, and shoreline 

 cottage owners. 



Construction 



Construction includes building activities associated with homes, walls, piers, 

 jetties, dams, industries, roads, parking lots, bridges, and walkways. 

 These developments exist in all regions of coastal Maine in varying extent and 

 generally relate to population density (see "The Socioeconomy" in chapter 2). 

 The impacts associated with construction are reviewed below. Impacts of the 

 various types of developments are covered by facility (e.g., piers and wharves 

 are discussed under "Ports and Navigation" above). 



In all aquatic systems, the adverse effects of construction projects include 

 loss of habitat, altered stream flow, increased turbidity, and increased 

 sedimentation, which forms a layer of silt and resuspensed pollutants from 

 benthic sediments. The impacts of construction vary with the type of 

 development, degree of landscape and drainage pattern alterations, density of 

 individual development projects, proximity of the operation to the water, and 

 the basic ecological sensitivity of the area (Clark 1974). The short-term 

 impacts of construction projects on the food web are similar to those of 

 dredging. Construction often promotes erosion, blocks sediment flow, and 

 redirects wave energy. 



The inevitable devegetation caused by construction in nearshore and adjacent 

 upland areas increases erosion. Erosion of cleared land usually results in 

 the introduction of a high load of sediment into watercourses. Palustrine and 

 lacustrine systems in coastal Maine are especially vulnerable to high sediment 

 loads, as water flow in these systems usually is restricted. 



Soil erosion is a serious but controllable problem. Unvegetated soil is 

 unstable and erodes into adjacent waters, causing siltation and sedimentation. 

 Soil particles in suspension cause turbidity in water, preventing light 

 penetration and thereby hindering photosynthesis and plant production. 



3-48 



