Introduction to Stream Restoration - Hydro-Environmental Analysis: Freshwater Environments - page 261

To p of
bank

Bottom of
bank

20-30

Flow

Rock vane

20-30

J-rock vane

FIGURE 8.45 Plan view of rock vane and J-rock vane. (Redrawn from Center for Watershed Protection, Inc.,
Fact Sheet: Stream Restoration: Flow Delection/Concentration Practices, Stormwater Manager's Resource
Center (SMRC), Ellicott City, MD, 2000. Available at http:\\www.stormwatercenter.net.)

8.4.29 S and t rapS
Sand traps are commonly designed to remove excess sediment from streams, such as for the protec-
tion of spawning gravels (Steen 2003), and are often used in conjunction with LWD placement. A
depression is typically dug in the channel to collect the sediments, and the deposited sediment is
subsequently removed. Sand traps are one of the most common methods for habitat improvement
listed in the NRRSS database, and the most common technique in the Midwest (Alexander and
Allan 2006).

8.4.30 u rban bMp S
Urban BMPs are generally accepted as practices that are intended to reduce the peak volume of
runoff or the pollutant content of nonpoint source discharges, such as pathogens or indicator spe-
cies (e.g., coliform bacteria), pesticides, organic materials, sediments, and nutrients. BMPs may
require some structural modiications or they may be nonstructural, such as education and public
involvement.
Many of the methods used for stream restoration discussed elsewhere in this chapter may also
serve to reduce peak lows or pollutant loads, such as restoration of riparian zones. Thus, while the
focus of the projects differ, the practices for pollutant load reduction and stream restoration produce
synergistic beneits.
This section will focus on urban BMPs, primarily those designed to address stormwater runoff.
Although agricultural BMPs were discussed separately, many of the BMPs are applicable to both
environments.
Urban BMPs have historically been primarily used to reduce stormwater runoff from urban environ-
ments to prevent looding. Generally, with urbanization the magnitude of stormwater runoff increases,