Yadkin - Pee Dee River Basin Plan 2008 Summary Hydrologic Unit Code 030401
Total Page:16
File Type:pdf, Size:1020Kb
Yadkin - Pee Dee River Basin Plan 2008 Summary Hydrologic Unit Code 030401 GENERAL DESCRIPTION The Yadkin-Pee Dee River basin is the second largest basin in North NC DWQ YADKIN - PEE DEE RIVER BASIN PLAN SUMMARY 2008 - PEE DEE RIVER BASIN PLAN SUMMARY YADKIN NC DWQ Carolina and covers approximately 7,213 square miles, spanning 21 BASIN AT A GLANCE counties. Originating on the eastern slopes of the Blue Ridge Mountains COUNTIES in Caldwell and Wilkes counties, the Yadkin River flows northeasterly for about 100 miles and then turns southeast until joined by the Uwharrie Alexander, Alleghany, Anson, Ashe, River to form the Pee Dee River. The Pee Dee River continues its southeast Cabarrus, Caldwell, Davidson, course through North and South Carolina to Winyah Bay at the Atlantic Davie, Forsyth, Guilford, Iredell, Ocean. Mecklenburg, Montgomery, Randolph, Richmond, Rowan, Increasing nutrient enrichment, urbanization, and wastewater are the Scotland, Stanly, Stokes, Surry, primary impacts to water quality in this basin. Most of these impacts are Union, Watauga, Wilkes, Yadkin focused in the counties of Forsyth, Rowan, Iredell, Cabarrus, Davidson, and Union. Land conversion from forest and agricultural practices to PERMITTED FACILITIES suburban uses is occurring nearly everywhere throughout this basin. Only protected natural areas and steep mountainous terrain are not impacted NPDES WWTP by these changes. Major: 40 Minor: 193 Despite these areas of concern, there are still streams in largely forested NPDES Nondischarge: 80 and comparatively undeveloped catchments with very good water quality. NPDES Stormwater Most of these waters are found in northern Wilkes, western Surry, and General: 647 portions of Montgomery County (Uwharrie National Forest). In fact, of the Individual: 37 51 streams and rivers classified Outstanding Resource Waters (ORW) in the Phase II 21 Yadkin-Pee Dee River basin, 73% are located in these counties. Animal Operations: 347 The Yadkin-Pee Dee River basin experienced moderate to severe drought AQUATIC LIFE SUMMARY conditions in 2001, which had the potential to reduce the impacts from Rivers & Lakes & nonpoint sources and magnify the impacts from point source discharges. Streams Reservoirs CURRENT STATUS (Miles) (Acres) Monitored 2,320 32,263 There are 94 impaired assessment units in the Yadkin Pee-Dee River 39% 92% (Figure 1/Table 1). Impaired waterbodies are those streams/lakes Supporting 1,284 12,796 not meeting their associated water quality standards in more than 10 55% 40% percent of the samples taken within the assessment period (January 1, 2002 through December 31, 2006) or those not meeting the narrative Not Rated 123 8,004 standards for either benthic macroinvertebrate community criteria or fish 5% 25% community criteria. Most of the stream impairments (26%) are based on Impaired 912 11,463 poor biological integrity measured by aquatic macroinvertebrates and 39% 36% fish communities, followed by turbidity violations (19%), low dissolved No Data 3,626 2,731 oxygen levels (6%) and elevated fecal coliform bacteria (4%). In lakes and 61% 8% reservoirs, chlorophyll a exceeds the standards in 36% of the total acres sampled, followed closely by high pH levels (35%) and turbidity in 17% of Total length 5,946 34,994 the samples. or area 1 NC DWQ YADKIN - PEE DEE RIVER BASIN PLAN SUMMARY 2008 - PEE DEE RIVER BASIN PLAN SUMMARY YADKIN NC DWQ 2 NC DWQ YADKIN - PEE DEE RIVER BASIN PLAN SUMMARY 2008 3 BIOLOGICAL SAMPLING FIGURE 2. The basinwide biological (fish and benthic community) sampling effort in theYadkin– Biological Community Pee Dee River basin increased by 12 percent between samples collected in 2001 Population Shifts 2001-2006 and samples collected in 2006; however, this increased effort did not significantly impact the ratio of supporting and impaired streams. Nineteen percent of the waters sampled between 2001 and 2006 showed an improvement in biological communities (Figure 2). There was a 17 percent decline in benthic and fish populations between Declined 2001 and 2006. Most declines were noted in areas along the urbanizing I-85 and I-40 17% corridors, particularly in western Cabarrus County. No Change 45% First Sample 19% AMBIENT SAMPLING Improved Problem areas were scattered throughout the basin. See 8-digit hydrologic unit code 19% (HUC) subbasin sections to get specifics on individual streams and lakes. The majority of North Carolina, including the Yadkin-Pee Dee River basin, experienced drought in 2002, and significant rains in 2003. These dramatic changes in flow appear to account for fluctuations for many parameters, including temperature, specific conductance, dissolved oxygen, pH, turbidity, and fecal coliform. Comparisons of the six hydrologic units (HU) within the Yadkin-Pee Dee River basin yielded the following: ·Physical Parameters; all HUs: • Temperature: The majority of variation in temperature is caused by seasonal and daily variation in solar radiation and air temperature. A slight increase in surface water temperature was detected in the South Yadkin HU. There were no discernible trends in the other five HUs. • Specific Conductance: Conductance peaked in 2002 during the drought. Similarly it reached its lowest point during 2003 and the end of the drought. Downward trends in conductivity values in the Yadkin River Headwaters, the Rocky River, and the Pee Dee River reflect the end of the drought and resultant dilution due to increased runoff and rainfall. • Dissolved Oxygen: Dissolved Oxygen was at its lowest during the 2002 drought. Increasing concentrations in the Yadkin River Headwaters, the Rocky River, and the Pee Dee River reflect the end of the drought. • pH: The ending of the drought in 2003 caused a steep decline in pH values throughout the basin. • Turbidity concentrations appear to be decreasing in the South Yadkin and High Rock Lake HUs and increasing in the Rocky River HU. Turbidity concentrations were low during the 2002 drought, rose in 2003, and have since stayed relatively even. • Fecal Coliform bacteria levels peaked during the 2003 rains, and has decreased since then. Significant downward trends are present in the Yadkin River Headwaters, the South Yadkin River, the High Rock Lake, and the Lake Tillery HUs. ·Nutrients in Yadkin River Headwaters & South Yadkin River 8-digit HUs: NC DWQ YADKIN - PEE DEE RIVER BASIN PLAN SUMMARY 2008 - PEE DEE RIVER BASIN PLAN SUMMARY YADKIN NC DWQ • Ammonia concentrations appeared to decrease slightly and do not appear to be related to the drought. • Total Kjeldahl Nitrogen concentrations appeared to be decreasing and do not appear to be related to the drought. • Total Nitrate and Nitrite concentrations peaked during the drought and were beginning to decrease after the drought ended. • Total Phosphorus concentrations appeared to decrease. Concentrations were slightly higher during the drought. • Nutrients in Lake Tillery HU: Total Nitrate and Nitrite concentrations appeared to increase slightly. • Nutrients in Rocky River HU: Total Phosphorus concentrations tended to be higher than in the rest of the HUs. 4 SIGNIFICANT ISSUES WATER QUALITY STRESSORS & SOURCES Rivers and Streams S tressor impairments are based on poor biological integrity measured by aquatic macroinvertebrates and fish communities, turbidity violations account for 19 percent, low dissolved oxygen levels six percent and elevated fecal coliform bacteria four percent. Stream miles impaired by these parameters are indicated in Figure 3. s are indicators or parameters that may cause water quality degradation. Twenty-six percent of stream F IGURE 3. S 500 450 TREAM 400 350 300 M Miles250 ONITORED 200 150 100 P 50 ARAMETER 0 When evaluating water quality stressors, DWQ evaluates and identifies the source of the stressor as specifically as possible depending on the amount of information available for that particular watershed. associated with the predominant land use where the altered hydrology is able to easily deliver the water quality S stressor to the waterbody. Factors that contribute to habitat degradation include increased impervious surfaces, sedimentation and erosion from construction, general agriculture, and other land disturbing activities. Sources identified as contributing to water quality degradation in the Yadkin- Pee Dee River basin are found in Figure 4. F a IGURE Chlorophyll 4. I High pH DENTI F IED 20% Turbidity S OURCE 16% Low DO 12% S C Percent ONTRIBUTING 8% Fecal Col. Bacteria 4% 0% TO Benthos W Fish Agriculture ATER Impervious Surfaces Q 2008 SUMMARY PLAN BASIN RIVER DEE PEE - YADKIN DWQ NC UALITY Stormwater Runoff Source MS4 NPDES D EGRADATION Na u al ond ion t r C it s s are most often Unknown WWTP NPDES IN Construction S TREAM Impoundments Failing Septic Systems S Land Clearing Road Construction Industrial Sites Animals 5 Lakes and Reservoirs FIGURE 5. LAKE IM P AIRED PARAMETER S For lakes and reservoirs in the Yadkin-Pee Dee River basin, nutrient overenrichment is the largest stressor as evidenced by 14,000 the high percentage of waters impacted 12,000 by high chlorophyll a levels and high pH (Figure 5). Turbidity and temperature 10,000 were the next most common stressors to these lake and reservoir systems. 8,000 Stormwater is the predominant stressor source for lakes and reservoirs in the acres 6,000 Yadkin- Pee Dee River basin (Figure 6). Stormwater is the flow of water that 4,000 results from precipitation and usually 2,000 occurs immediately following a rainfall. Common stormwater pollutants include 0 sediment, nutrients, organic matter, bacteria, oil and grease, and toxic Chlorophyll a High pH Turbidity substances (i.e., metals, pesticides, herbicides, hydrocarbons). Stormwater can also impact the temperature of a surface waterbody, which can affect the water’s ability to support healthy aquatic communities. FIGURE 6. IDENTI F IED SOURCE S CONTRIBUTING TO WATER QUALITY DEGRADATION IN LAKE S 60% 50% 40% 30% Percent 20% 10% 0% Agriculture Stormwater Natural WWTP Impoundments Runoff Conditions NPDES NC DWQ YADKIN - PEE DEE RIVER BASIN PLAN SUMMARY 2008 - PEE DEE RIVER BASIN PLAN SUMMARY YADKIN NC DWQ Nutrients Nutrients are significantly impacting lakes throughout the basin as evidenced by algal productivity.