Environmental Engineering Reference
In-Depth Information
the restoration of publicly owned lakes. The initial focus of the Section 314 grants program was on
research, the development of lake restoration techniques, and the evaluation of lake conditions. The
speciied evaluation of lake conditions by individual states included:
•
A classiication of the eutrophic condition of the state's publicly owned lakes
•
A description of the methods for controlling sources of pollution of those lakes
•
A description of the methods and procedures to restore the quality of those lakes
•
A list of those publicly owned lakes known to be impaired, which are then to be included
in the state's annual 305(b) report
The evaluations were stipulations for the receipt of funds under this program. In the early years,
there was substantial funding for this program, with in excess of $145 million distributed. However,
although reauthorized in 2000 (as part of the Estuaries and Clean Water Act of 2000), no funds have
been allocated for this program since 1994, so that it presently exists only on paper.
Section 314 funding, when it was available, provided funding for a variety of data collection
efforts. Data are critical for all stages of lake management and restoration, and usually long-term
data are required in order to establish trends, both spatial and temporal. In addition to trend data, data
are required for predictions, relating trends (effects) to causes. For example, trend data may include
periodic water quality data at speciic horizontal and vertical stations within a lake. Predictive mod-
els also require lows and loadings (based on lows and concentrations) for all sources impacting the
lake. Data are expensive, and inding sources of funding for data collection and implementing and
maintaining data collection efforts are an essential component of lake management and restoration.
In the absence of 314 funding, some federal funding is provided under Section 319 of the CWA.
Section 319 is targeted at nonpoint source control, such as urban and agricultural runoff. While
nonpoint source pollution is important for lakes and reservoirs, this program is not targeted toward
lakes, so that lakes and reservoirs are only one waterbody type of interest. While some federal
funding is periodically available under other programs (e.g., U.S. EPA 2008 Watershed Survey) or
legislation targeted to speciic waterbodies (e.g., Lake Tahoe), funding for lake restoration remains
problematic and often relies solely on local or state sources.
17.3 CONTROL AND MANAGEMENT OF SEDIMENTATION
One of the major issues impacting many lakes and reservoirs is sedimentation, not only because
of its impact on water quality but also because of its impact on life expectancy. For example, the
classical view of lake succession is that lakes are temporary ecological systems, formed in some
depression that will eventually ill in to become a terrestrial environment, or become extinct. That
timescale varies enormously for natural lakes, if it is applicable at all.
For reservoirs, the rates of sedimentation are generally greater since they are designed to store
water from the low of the rivers and streams that they dam. They also store much of the sediments
contained in those lows (acting as sediment traps). Traditionally, most reservoirs are considered to
be sediment traps so that, ultimately, they may be illed in unless the sediments are removed the
dams are destroyed by loods or are removed.
The control and management of sedimentation in reservoirs include both external source control
and the control of lake shorelines. The erosion of lake shorelines not only impacts sedimentation, but
it also impacts many other ecological characteristics of lakes. The U.S. Environmental Protection
Agency's (EPA) 2010 National Lakes Assessment reported that lakes with poor lakeshore habitats
are three times more likely to be in poor overall biological condition than lakes with good quality
shorelines. The EPA maintains a website as a clearinghouse for information on lakeshore protection
and restoration.
Since the sediment directly impacts the storage capacity and purpose of reservoir projects, quan-
tiication (e.g., through sedimentation surveys) and control of that sedimentation are an integral
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