Here is a graph of the effluent from the Fearrington waste water treatment plant. The rated capacity of the plant is 270,000 gallons a day. It averages 63% of capacity. The chart summarizes the 2012 data for the 5 effluent characteristics that have limits:
- Overall Capacity
- Chlorine
- Biochemical Oxygen Demand (BOD)
- Nitrogen
- Solids
It looks good except for the residual chlorine, which averages 125% of the allowed limit. However, the Division of Water Quality has a policy that any TRC value less than 50 ug/l is deemed compliant.You will need to hover your mouse over the chart to get the exact descriptions and values. Any chemists around? The complete data is here. No limits are specified for some characteristics, i.e. temperature, which is just monitored.
Here's what I have learned from the data so kindly shared with us by the Haw River Watch
In the Haw Basin (slightly pink background), 41 stream sites monitored by volunteers are listed as active. although only 30 of these have reports from 2012. This data is based on the most recent report from the 41 sites monitored in 4 counties. The data is reported on these forms.
Overall stream health is scored by counting invertebrates in 3 categories
- Pollution Sensitive
- Somewhat Pollution Sensitive
- Pollution Tolerant
Based on this rather straightforward assessment, the two sites in Fearrington
- Bush Creek North Fork (BushCrNF) - score 13 (just downstream from the Fearrington waste treatment plant)
- Bush Creek South Fork (BushCrSF) - score 6 (on Millcroft at Woodham)
Rank 26th and 33rd respectively
The maximum possible score is 48
Three sites with zero scores have no data for invertebrate count
Here's the graph and the map:
- red flag - score 1-8
- red dot - 8-16
- yellow dot - 16-24
- green dot - 24-32
- green flag - 32-40
- blue flag - missing or zero invertebrate count
And here's a first pass at mapping the thousands of values of the dozens of data points from the Division of Water Quality at the NC Department of Environment and Natural Resources. This represents the average nitrate readings at 66 sites in the Haw Watershed.
- Red flags top quarter
- Red dots 3rd quartile
- Green dots 2nd quartile
- Green flags bottom quarter
