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Water quality

Raystown Lake is considered a monomictic lake and is currently designated as a Cold Water Fishery. A monomictic lake is a lake that is stratified in the late spring and summer and constantly mixed in the fall and winter. Stratification refers to varying temperature levels within the lake (epilimnion, metalimnion, hypolimnion). Raystown also does not completely freeze over. Raystown Lake used to be a dimictic lake (one that mixes in the spring and fall and stratifies in the summer and in the winter due to it being completely frozen) but no longer completely freezes in the winter months.

One of the major concerns with many people have with Raystown Lake is the status of the water quality and much of this stems from possible impacts to the recreation around the lake. However, very little has been done to study the water quality and its implications on Raystown Lake. The lack of current water quality studies is something that needs to be taken into consideration. The lake is a major source of income for the area and low water quality can be very detrimental to the resorts and recreational sites on the lake. Along with this is the quality of the fishing available. Fishing is a very large attraction for this lake, and changes in water quality can affect the quality of fishing available for tourists. Basic environmental standards are another reason that a careful watch has been placed on Raystown Lake. There have also been concerns with local farming, waste and run off, and acid mine drainage affecting the quality of the lake. Point source and non-point sources of pollution have also been studied.

When looking at the water quality of any body of water, several important things should be discussed including phosphates, dissolved oxygen levels, temperature, and nitrates. These tests can give an overall idea as to the general quality and health of a lake. While the testing of soluble phosphates is a reliable study, it tells very little about the lake due to the fact that most soluble phosphate within the water is held within algae, plankton, and sediments. What this means is that the test for soluble phosphates cannot accurately portray the amount of soluble phosphate within the water column. Phosphate, however, is a very good indicator of certain types of pollution as it causes algal blooms. Phosphate is normally a limiting factor to the growth of algae. When there is a large explosion in the algal populations within a body of water it sometimes means that there has been an influx of nutrients, in many cases its phosphate.

The best placed to begin looking at the water quality of the lake would be around the Saxton area because it is the ‘beginning’ of the lake. The water flowing into Raystown Lake is very anoxic, low in oxygen levels to the point where there is virtually no dissolved oxygen within the water. This would be considered unhealthy in terms of water quality due to the fact that many organisms require dissolved oxygen to survive. In an ongoing, unpublished study by Sharon Yohn (1998 to current) there was found to be a little as 1.0 mg/L of dissolved oxygen near Saxton and as much as 6-7 mg/L of dissolved oxygen near the dam in July 1998.6 Dissolved oxygen levels increase as they near the dam, and increase dramatically after the dam due to physical aeration of the water, especially when water is released from the floodgates. To compare, cold water fish (ex. Trout) need about 6-7 mg/L of dissolved oxygen to survive.5

In an unpublished study done in 2001, student Christopher Haley (now graduated) and Professor Dr. Larry Mutti of Juniata College, nitrate levels were measured at several locations around the lake. At a testing site down stream from Saxton, nitrate levels were shown to range from about 1.1 mg/L to about 0.3 mg/L during a sampling time period from May to October. At the end of the lake, near the dam, nitrate levels vary from a little over 1.0 mg/L to about 0.5 mg/L over the same time range. For a comparison, excessive levels of nitrate are generally about 5 mg/L or more.4

Shoup’s run, located in northern Bedford and southern Huntingdon counties includes the Broadtop region, a known site for acid mine drainage. Shoup’s Run and the Broadtop coal region contribute a large majority of the acid mine drainage to the Raystown Lake. Currently, several grants have been awarded to the Shoup’s Run Watershed Association to aid in the restoration and increase of water quality in the area.3

Look for future studies that could be done, questions to be asked. There are a lot of them because there is very little research done on the lake as of now. Ask the Chuck/Sharon Yohn what types of questions they want to see. Could also ask Mutti and Gus. what questions they have. Could also reference profs (i.e. Gus, Mutti, Yohn(s)) and date (i.e. as of 2004/2005, such and such is interested in this type of studies on the lake. Refer to them if you are interested).

Another problem associated with increased sedimentation is that sediments can be a sink for pollutants^lxxxiii. Substances like PCB’s, heavy metals, pesticides, oil and grease, coliform bacteria, and mutagenic substances can be found^lxxxiv. If these sediments are disturbed, they can release many different pollutants into the reservoir or even into the stream system^lxxxv. But if these sediments are not disturbed they can provide a way to remove some harmful pollutants from a stream system.

Increased sedimentation within reservoirs can also cause increased erosion downstream from the dam^lxxxvi. Water released from the dam attempts to “re-establish” the former balance of water and sediments, causing increased erosion directly downstream from the dam^lxxxvii. This erosion can cause undercut banks along the river^lxxxviii.

Sediment can also impact reservoirs by increasing turbidity^lxxxix. Turbidity can affect water quality by decreasing the amount of light that can penetrate into the water column, which consequently can limit or prohibit the growth of algae and rooted aquatic plants^xc. There is also the possibility that a highly turbid reservoir could be hypertrophic, in which case there could be a tremendous growth of algae and rooted plants^xci. But in this situation, the turbidity would act as a limiting factor for the growth of these plants and keep their growth to a minimum^xcii.