The Environmental Impacts of Water Infrastructure Planning

Loss of Habitat from Reservoir Construction

1. Located where dam is cheapest and greatest storage per area. Also where the animals live; i.e., no houses, historical problems, waste dumps, etc. Animals and trees have no "standing". Endangered species the one big exception.

2. Bottomland forest and fresh marsh covered with water. Low gradients so a lot of backwater impacts. These areas are well recognized flight paths for waterfowl and tree perching birds as they move from north to south and back. Cover and shelter for them.

3. Development around a reservoir due to concessionairing and housing. More habitat gone.

Filling Impacts

4. White’s work on Toledo Bend: important factor in white shrimp decline. I looked at 10 years before and after filling. There was delay of flows (storage in spring and release in summer) to later in year due to storage and use during peak demand. Impact on bay salinities could not be correlated.

 

Alteration of Flows

1. System management of reservoirs. Lower reservoir & then reservoir with smallest watershed/storage area. Water moves to new watershed and use is evened out thoughout the year. Seasonal salinity regime impacted which controls movements of many estuarine plankton and juvenile shrimp and fish.

2. Change in base flow regime. Base flows are inflection. Different between dry, average, and wet years. The fishery is adapted to these. Reservoirs would reduce these and supply only dry year base flow. Loss of riffle water and the use of developed edges where fish seek protection

3. Change in small flooding regime and its impact on backwater sloughs separated by shoals. Composition of bottomland forest trees will change due to reduced flooding and replacement with the wrong tre species. Old trees die and replaced with more mesic species

Aqueducts

1. Loss of forest interior. We have plenty of edge. Change hydrology as they cross low lying areas. Interbasin transfers a new science for impact studies. Changes in water quality, status of pathogens, adaption of wetland plants to a new and changing substrate.