Beaver Lake Water Quality Summary: [Appendix H]

Appendix H

[ 4 Pages ]

Beaver Lake and Streams Water Quality Summary

Spatial & Temporal Trends of Buncombe Co. Streams from 1990-2009

(Water Quality Sampling Data & VWIN)

UNCA Limnology Class Reports (Dec. 2000, Fall 2001, Nov. 2003)

Beaver Lake and Streams Water Quality Summary

For the management plan, more data is required to understand the current water quality of Beaver Lake, where there may be problems in the future and what steps may be taken to prevent future water quality concerns. Water quality of Beaver Lake and the streams entering the lake have been monitored over the years by various organizations at various seasons and for various reasons. The best data came from the monitoring network Volunteer Water Information Network (VWIN) run by the Environmental Quality Institute (EQI) at UNC-Asheville and sampled by volunteers on a monthly basis during the period 1990-2001 (see Appendix G). The Metropolitan Sewerage District supported the sampling network from 2003 until 2009 when the lab was closed at UNC-A.
(The EQI in 2011 is established as a private non-profit lab and again assisting volunteers throughout western NC). Beaverdam Creek (Site 8), South Creek (Site 39- parallel to Merrimon under the library) and the pond on South Creek (Site 48-Bird Sanctuary) have been a part of this monitoring program for many years and it has a good data base for analyzing the water quality of the streams entering the lake. The two side tributaries paralleling Avon and Euclid and entering the lake as one outfall and the tributary along Midland Dr./Edgelawn Road have not been part of any long term monitoring program and no data could be found for this report except for reports of sewer leaks in the 1970-1990’s. There is also a small database and 4-5 reports from the fall semester course on limnology in the early 2000’s taught by Dr. Rick Maas of 4-5 reports (See Appendix G). Some consultants provided a one time snapshot measurement at one site during their studies on fishing and other projects.

In the 2009 report of Spatial and Temporal Trends of Buncombe County Streams from 1990 through 2009 by EQI, Beaverdam Creek was rated as Average; both South Creek and the South Creek pond were rated as Poor in water quality (See attached report in Appendix G). Problems in both creeks include sediments (turbidity, total suspended solids), metals (from urban and road runoff), and nutrients. Both of these creeks can impact the water quality of Beaver Lake with these chemical loads and cause problems within the lake. These parameters are typically found to be impacted in urban and developing areas and may never return to the low levels observed in protected watersheds (Bent Creek, etc.). South Creek pond sampling site has been dropped in 2010 from the sampling program due to funding issues, but the water quality in South Creek will continue to be monitored at this time. LVP should encourage and request the MSD and Buncombe County continued support of water quality monitoring in order to monitor the impacts coming into the lake due to the poor water quality that has been documented in the past.

The lake water quality data primarily came from the fall database from the UNC-A classes. They noted some parameters of concern to lake managers. The PO4 (phosphorus) levels ranged widely in the lake during the periods 1996-2003, from 0.01 to 0.50 mg/l (or ppm). Phosphorus in lakes can cause excessive plant growth in any levels from 0.05 and up, so the many measurements of 0.1-0.5 by the students indicate that macrophytes and algae could become a concern at any time. This data is tempered somewhat by the fact that each data point was analyzed by a different student each year over the years and not certified lab technicians as was the case in the VWIN database. The nutrient data do support the growth of the weedy, invasive species that have been observed in past years in Beaver Lake. What is not clear is where the nutrients are going when the plants are controlled (die off, grass carp, etc.). The cycle of nutrients means that the plants are converted back to basic nutrients by the carp and excreted in 

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their wastes. The only way to remove them from the lake is flushing by water flows out of the lake, or conversion to another plant species, like single cellular algae. The removal of sediments in the early 2000’s did remove a source of nutrient deposition, but fresh sediments have replaced and filled in the areas cleaned out.

WES has observed that the lake does have a distinct green color in late summer, an indication that the algae population that may be fairly high. There is no information on the species of algae present in the lake, or whether it will tend to create algae bloom conditions or toxin releases. This condition seems to have been consistent over the years, and the algae population has rarely created algae blooms of any length or problem.

WES took field measurements of the lake at the discharge weir on August 26, 2011. This was the best time for the worst conditions for lake monitoring – hot, sunny days create chemical and physical conditions in the lake that can be a major source of problems. WES found that, unlike the UNC-A data that monitored conditions later in the fall, there was a definite thermocline established in the lake, with low oxygen levels first encountered at 10 ft depths (3.0 m);  temperatures were in the upper 70’s to mid-80’s (21.1C to 30.0C at the surface). The color of the water was green, and the visibility as measured with a Secchi disk was only 33.0 inches (0.85m). This was a snapshot, but these high temperatures, low dissolved oxygen, and lot of algae growth are symptoms in lakes of stressed conditions that could result in future problems.

There is one factor that is probably playing a large role in the apparent stable water quality of Beaver Lake and that is the amount of water that passes through the lake. Pinnacle Engineers, as part of their evaluation of the hydrology of the lake and floodwater, did a rough calculation of the retention time of the water in the lake – how much time it takes to completely replace the water in the lake with water coming in from the streams (think of a bathtub – when the water coming into the tub completely replaces the volume of water that was in the tub). They based it on the original depths of the lake (no data on the current depth due to sedimentation) and during normal flows (faster during high flow events). They calculated a complete replacement would occur in 7-10 days for Beaver Lake, a very quick turnover rate. Problems with water quality generally shown up in lakes with replacement periods on the order of year(s). So even though the streams are bringing in poor to average quality of water to the lake, the nutrients and pollutants are not remaining in the system long enough to create problems or are being diluted quickly by the next high water event. This has helped prevent Beaver Lake from experiencing many of the major water quality issues that other lakes have experienced with the same nutrient loads coming into the lake.

Recommendations:

WES recommends strengthening partnerships with agencies to help clean up and protect the water quality of the streams entering Beaver Lake. This effort will provide the most long term protection of the lake water quality. It will also help to reduce the cost and efforts of siltation required as discussed in the sediment section of this report. Support for the local stormwater programs which will help to protect the water quality of stormwater runoff into the streams and the lake itself would be proactive for protecting Beaver Lake. specially within the LVP

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neighborhood, information and education would be essential to preventing any household discharges from reaching the lake.

There are grants and funding available for lake managers in North Carolina for addressing water quality  ssues. These are not available to LVP unless a non-profit foundation is established.  LVP does have volunteers who are pursuing the non-profit organization status for the community. Another option is to partner with the City of Asheville and have grant funds run through the city. This limits some of the grants as the City is not eligible for certain grants because they are part of the Stormwater Phase II program run by EPA/NCDENR. Other organizations may partner with LVP on individual projects on a case by case situation (Land of Sky Regional Council, North Carolina Lake Management Society, Audubon, etc.). This is to be encouraged as it will help achieve LVP goals. LVP Commission meetings indicate that the community has volunteers who are willing and active in researching possible grants and funding for these projects. The Audubon affiliated bird sanctuary has had success in past grant applications for the construction of the sanctuary trails and wetland areas, and is currently applying for further grants to clean out the wetlands that were impacted by the floods of 2000-2001

This report must note that the data that would support or determine the actual water quality and health of Beaver Lake are not present. There is not a long term database available on dissolved oxygen, temperature, conductivity, bacteria, nutrients or any other important monitoring parameter that can track the lake’s health, especially in the summer months when conditions are usually at the worst state (see Appendix G). The UNC-A data is during the fall months, after lake turnover occurs, so the worst case conditions are not present like they would be in late summer. No data from the smaller streams exist and thus it is not known whether there are water quality concerns in those drainages or not. Whether the lake is just about to have a problem or not cannot be predicted. Monitoring data would provide LVP with the ability to know what is occurring in the lake and the feeder streams and how the changing seasons and quality of runoff are impacting the water quality in the lake.

Monitoring of these inputs can be an important part of managing the water quality of Beaver Lake. LVP should encourage and support water quality efforts by the state and local governments to measure and control this impact. It is recommended that LVP invest in their own monitoring of these inputs if other agencies are not. This provides the data that is needed for management decisions and legal options when problems arise from the watershed. To be pro-active, a volunteer monitoring effort with analyses run by the EQI lab would be the most cost effective method of obtaining this information.

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