8209

• UCREFRP Catalog Number: 8209
• Author: Rochester, H., T. Lloyd and M. Farr.
• Title: Physical Impacts of Small-Scale Hydroelectric Facilities and Their Effects on Fish and Wildlife.
• USFW Year: 1984.
• USFW - Doc Type: 14-16-0009-82-020,
• Copyright Material: NO

populations (Fig. 4). SSH may be the least destructive among various
energy alternatives for a given site and, therefore, contribute to reducing
env i ronmenta 1 degradat i on from other causes. However, each site must be
considered individually to determine if SSH is less environmentally
damaging than competing energy options.

2.2 CONFLICTS OF SMALL-SCALE HYDRO WITH OTHER USES

2.2.1 Fish and Wildlife Conflicts

Based on experience with various hydro projects and other activities that
affect rivers, several important concerns associated with SSH projects have
been identified. The most signficant SSH impacts can be grouped as
follows:

1. Blockage (and mortality) of both upstream- and downstream-
migrating fish by dams, diversion structures, turbines,
spillways, and waterways;

2. Alteration of stream and riverine habitats, natural lakes,
riparian areas and wetlands by inundation, dewatering, chan-
nelization, and filling;

3. Changes in water quality, including sediment transport dis-
solved oxygen, and water temperature;

4. A 1 terat i on of flow reg imes, both increases and decreases,
which makes otherwise suitable riverine habitats unfit for
aquatic invertebrates, fish, amphibians, and reptiles, and,
possibly, dependent riparian species;

5. Fluctuating instream flows and reservoir levels, which make
habitats too unstable for full utilization and may degrade
water quality;

6. Disturbance of fish and wildlife and their habitats from
construction activities, increased numbers of visitors to
sites, road dust, oil and toxic waste spills, noise from
some hydroelectric equipment, and site lighting, blasting,
and waste releases;

7. Damage to terrestrial habitats and soils, disruption of run-
off patterns related to road building and transmission line
clearance, and creation of borrow pits and spoil disposal
sites;

8. Direct effects of transmission lines on fish, wildlife and
their habitats.

9. Long term changes in river hydrology, including possible
changes in flow regime, the river's contribution to ground

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