Section 9
Implementation Plan for Bonnie Creek Watershed
v 9-5
FINAL REPORT
9.2 Implementation Actions and Management Measures for
Dissolved Oxygen
DO impairments are addressed by focusing on organic loads that consume oxygen
through decomposition and nutrient loads that can cause algal growth, which can also
deplete DO. Analysis provided in Section 7 established a relationship between
reaeration, BOD5, and DO concentrations in Galum Creek segment NCD05, so
management measures for segment NCD05 will focus on increasing reaeration and
decreasing BOD5 loads to increase DO concentrations. Although it was shown that
based on current data, BOD5 loads do not need to be reduced, it is likely that during
storm events, high BOD5 loads are transported to the stream, and therefore reducing
these loads will also help increase DO concentrations.
DO impairments in Galum Creek segment NCD05 are mostly attributed to low flow or
stagnant conditions within the creek. Runoff from nonpoint sources may also
contribute a BOD5 load in Galum Creek segment NCD05. An additional contributor to
low DO is increased water temperatures. Therefore, management measures for
segment NCD05 will focus on reducing nonpoint source loading through sediment and
surface runoff controls, reducing stream temperatures, and reducing stagnant
conditions through reaeration.
Implementation actions, management measures, or BMPs are used to control the
generation or distribution of pollutants. BMPs are either structural, such as wetlands,
sediment basins, fencing, reaeration structures, or filter strips; or managerial, such as
conservation tillage, nutrient management plans, or crop rotation. Both types require
good management to be effective in reducing pollutant loading to water resources
(Osmond et al. 1995).
It is generally more effective to install a combination of BMPs or a BMP system. A
BMP system is a combination of two or more individual BMPs that are used to control
a pollutant from the same critical source. In other words, if the watershed has more
than one identified pollutant, but the transport mechanism is the same, then a BMP
system that establishes controls for the transport mechanism can be employed.
(Osmond et al. 1995).
Implementation actions and management measures are described for each nonpoint
source in the watershed. Nonpoint sources include cropland, rural grassland, and
animal management facilities.
9.2.1 DO Concentration Management
The sources of nonpoint source pollution in the Bonnie Creek TMDL are divided
between agricultural cropland, rural grasslands, and animal management facilities.
BMPs evaluated for treatment of these nonpoint sources are:
filter strips
wetlands
