Publication Date:
2021-05-19
Description:
Several studies illustrate the conflicts between water resource management and the quality of estuarine habitats. Nichols et al. (1986) describe how, in California (U.S.A.), the flow from two major tributaries to San Francisco Bay (San Joaquin and Sacramento rivers) has been reduced to less than 40% of historic levels. Most of the historic flow upstream in the watershed is now hold in reservoirs for use by agricultural and urban consumers during dry California summers. The projects upstream have resulted in three major ecological impacts: (1) collapse of the salmoid fisheries which is directly attributable to the construction of the Shasta Dam, (2) reduced freshwater inflow together with overfishing resulted in the decline in abundance of sturgeon, sardines, flatfish, crabs, and shrimp, and (3) the diminished freshwater inflow is probably responsible for the reduction of the capacity of this estuary to dilute, transform, or flush contaminants that are diluted into San Francisco Bay (Nichols et al., 1986). Even when changes in volumes of groundwater discharge are small, alteration of timing of freshwater flow can result in negative impacts in the estuarine ecosystems. Since 1900 twenty eight dams have been constructed on the Columbia River (U.S.A.). Management policies have reduced springtime freshwater flows to 50% of former levels, while fall discharges have been artificially increased by 10-50% (Simenstad et al., 1992). These changes had a negative effect on salmon fisheries in the region.
Description:
Published
Keywords:
Ground water
;
Groundwater pollution
;
Water management
;
Water quality
;
Water conflicts
;
Water policy
Repository Name:
AquaDocs
Type:
Report Section
,
Not Known
Format:
pp.105-113
