2001 Roanoke Sec B Chap 10

Section B: Chapter 10 - Roanoke River Subbasin 03-02-10 152
Chapter 10 -
Roanoke River Subbasin 03-02-10
Includes the Cashie River, Roquist Creek and tributaries
10.1 Water Quality Overview
The Cashie River and its tributaries including Roquist,
Hoggard Mill and Wading Place Creeks are contained
within this coastal plain subbasin. All streams, including
the Cashie River itself, are slow moving and swampy in
nature. Windsor, Askewville and a portion of Lewiston-
Woodville are the only municipalities. A map of this
subbasin including water quality sampling locations is
presented in Figure B-10.
Bioclassifications for sample sites in this subbasin are
presented in Table B-25. Use support ratings for each
applicable category in this subbasin are summarized in
Table B-26. Refer to Appendix III for a complete listing
of monitored waters and further information about use
support ratings.
Land use in the area is primarily forest with a mixture of
agricultural activities. Several animal operations are
located in the upper section of the Cashie River watershed. Timber is harvested in portions of
the watershed as well.
There are four dischargers in the subbasin. Only the Town of Windsor’s WWTP discharge,
flowing into an unnamed tributary to the Cashie River, is considered major; this WWTP is also
the only facility required to perform toxicity testing on its effluent. Toxicity problems have been
identified over recent review periods. The Cashie River and this facility are discussed in more
detail in the following sections.
Extensive evaluation, conducted by DWQ, of swamp streams across eastern North Carolina
suggests that different criteria should be used to assess the condition of water quality in these
systems. Swamp streams are characterized by slower flow, lower dissolved oxygen, lower pH,
and sometimes very complex braided channels and dark-colored water. DWQ has developed
draft biological criteria that may be used in the future to assign bioclassifications to these streams
(as is currently done for other streams and rivers across the state). However, DWQ believes that
there has been insufficient sampling of reference swamp streams to assign these
bioclassifications and use them for use support determinations in the Roanoke River basin.
DWQ continues to work toward preparing these criteria for future use.
Subbasin 03-02-10 at a Glance
Land and Water Area
Total area: 307 mi
2
Land area: 290 mi
2
Water area: 17 mi
2
Population Statistics
1990 Est. Pop.: 17,300 people
Pop. Density: 60 persons/mi
2
Land Cover (%)
Forest/Wetland: 79.2
Surface Water: 0.6
Urban: 0.3
Cultivated Crop: 19.4
Pasture/
Managed Herbaceous: 0.6
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Section B: Chapter 10 - Roanoke River Subbasin 03-02-10
Table B-25 DWQ Monitoring Locations and Benthic Macroinvertebrate Bioclassifications
(1999) for Roanoke River Subbasin 03-02-10
Site Stream County Location Bioclassification
Benthic Macroinvertebrates
B-3* Cashie River Bertie SR 1219 Not Rated
B-4 Cashie River Bertie SR 1257 Not Rated
B-5 Hoggard Mill Creek Bertie SR 1301 Not Rated
B-6 Wading Place Creek Bertie NC 308 Not Rated
B-7 Roquist Creek Bertie US 13/17 Not Rated
Fish Tissue
FT-8 Cashie River Bertie Windsor N/A
Ambient Monitoring
N8950000 Cashie River Bertie SR 1219 N/A
* Historical data are available; refer to Appendix II.
Historical data are only available for sites along the Cashie River in this subbasin. All of the
tributaries sampled by DWQ in 1999 were sampled for the first time. The lower Cashie River
and Hoggard Mill Creek sites showed little deviation from natural swamp conditions. The upper
Cashie River site, Roquist Creek and Wading Place Creek showed some signs of impacts to
water quality from the watershed.
Water chemistry samples are collected monthly from the Cashie River near Lewiston-Woodville.
Low dissolved oxygen concentrations occurred frequently; 55 percent of samples over the past
five years were less than 4.0 mg/l. Lower pH was also observed. Iron exceeded the reference
value in over 81 percent of samples; however, water passed chronic toxicity tests conducted by
DWQ in July 2000. Fecal coliform exceeded the 200 colonies/100ml water quality standard in
almost 22 percent of samples. Nitrogen, phosphorus and turbidity were also elevated compared
to other Roanoke River coastal plain stations.
In 1999, 24 samples, representing largemouth bass, bowfin, black crappie, sunfishes and
catfishes, were collected from the Cashie River above Windsor and analyzed for metals
contaminants. Thirteen samples (of mainly largemouth bass and bowfin) or 54 percent of
samples contained mercury concentrations exceeding EPA or FDA screening values of 0.6 µg/g
and 1.0 µg/g, respectively. All other metal contaminant concentrations were less than the federal
or state criteria. Refer to Appendix II for details about fish tissue collections.
For more detailed information on sampling and assessment of streams in this subbasin, refer to
the Basinwide Assessment Report - Roanoke River Basin (DENR-DWQ, May 2000), available
from DWQ Environmental Sciences Branch at http://www.esb.enr.state.nc.us/bar.html or by calling
[phone].
Section B: Chapter 10 - Roanoke River Subbasin 03-02-10 155
Table B-26 Use Support Ratings Summary (1999) for Monitored and Evaluated
1 Freshwater
Streams (miles) in Roanoke River Subbasin 03-02-10
Use Support
Category
FS PS NS NR Total
2
Aquatic Life/
Secondary Recreation
0 0 0 149.1 149.1
Fish Consumption 0 47.6 0 0 47.6
Primary Recreation 0002.32.3
Water Supply 00000
1 For the fish consumption use support category, only monitored stream miles are presented.
2 Total stream miles assigned to each use support category in this subbasin. Column is not additive
because some stream miles are assigned to more than one category.
10.2 Status and Recommendations for Previously Impaired Waters
This section reviews use support and recommendations detailed in the 1996 basinwide plan,
reports status of progress, gives recommendations for the next five-year cycle, and outlines
current projects aimed at improving water quality for each water. The 1996 Roanoke River basin
plan identified one impaired stream in this subbasin. The Cashie River is discussed below.
10.2.1 Cashie River (24.3 miles from source to SR 1257)
1996 Recommendation(s)
The 1996 basin plan listed the Cashie River as partially supporting. However, DWQ has since
determined that this site was inappropriately rated due to the swamp characteristics of the river.
The recommended strategy was to evaluate the contribution of agricultural runoff in the upper
portion of the watershed and implement BMPs as needed.
Status of Progress
In 1999, verification of swamp stream characteristics at SR 1219 in Bertie County was made, and
the previous bioclassifications that were inappropriately assigned to the benthic community were
adjusted. Since benthos data are not currently used to determine impairment in the biological
communities of swamp streams, the benthic community in the Cashie River is not rated.
Therefore, aquatic life is no longer considered impaired. However, the Cashie River is impaired
because of a fish consumption advisory and is discussed further in the following section.
10.3 Status and Recommendations for Newly Impaired Waters
The Cashie River was rated as impaired (partially supporting) based on the statewide bowfin
consumption advisory and recent DWQ fish tissue monitoring (1995-1999). This section
outlines the potential causes and sources of impairment and provides recommendations for
improving water quality.
Section B: Chapter 10 - Roanoke River Subbasin 03-02-10 156
10.3.1 Cashie River (54.6 miles from source to the Roanoke River)
Current Status
Bowfin with levels of mercury that exceed the NC action level for consumption were collected
by DWQ in the Cashie River above Windsor in 1999. Because of the statewide bowfin
consumption advisory, this portion of the river is only partially supporting the fish consumption
use support category. (Note: This is not a new advisory, but improved use support methodology
now bases impairment for the fish consumption use support category on fish consumption
advisories. See Appendix III for more information regarding use support ratings.)
2001 Recommendation(s)
DWQ will continue to monitor fish tissue in the Cashie River and will work to identify sources
of mercury. Given the global scale of mercury cycling, it may be difficult for DWQ to recognize
significant reductions of mercury in fish over the short-term. Section A, Part 4.8 provides more
details about mercury in the environment.
10.4 Section 303(d) Listed Waters
Currently in this subbasin, there are no waters listed on the state’s year 2000 §303(d) list (not yet
EPA approved). All waters in the state will likely be added to the list in 2002 as partially
supporting because of the statewide bowfin consumption advisory. Appendix IV contains more
information on the state’s §303(d) list and listing requirements.
10.5 Other Issues and Recommendations
There are no specific other issues for surface waters in this subbasin; however, recent DWQ
monitoring revealed habitat degradation impacts to aquatic life resulting from nonpoint source
pollution. Although no action is required, voluntary implementation of BMPs is encouraged and
continued monitoring is recommended. Section A, Chapter 4 contains general information and
recommendations about habitat degradation and other water quality problems that affect more
than one watershed in the basin. Additionally, education on local water quality issues is always a
useful tool to prevent water quality problems and to promote restoration efforts. Nonpoint
source program descriptions and agency contacts are listed in Appendix VI.