Coal Run (North Branch Buffalo Creek tributary)

Coal Run is a tributary of North Branch Buffalo Creek in Union County, Pennsylvania, in the United States. It is approximately 3.6 mi long and flows through Lewis Township and West Buffalo Township. The watershed of the stream has an area of 5.33 sqmi. A few streams in its watershed are designated as impaired due to nutrients and siltation. The watershed mostly consists of agricultural and forested land. Wild trout occur within the stream.

Course
Coal Run begins near a valley in Lewis Township. It flows southeast for several tenths of a mile before entering West Buffalo Township. Immediately upon entering that township, the stream turns east-southeast for several tenths of a mile, receiving one unnamed tributary from the left. It then flows east for a few miles, receiving three more unnamed tributaries from the left. After a while, it turns east-southeast for a few tenths of a mile before turning east again and receiving another unnamed tributary from the left. The stream then flows east-northeast for several tenths of a mile until it reaches its confluence with North Branch Buffalo Creek.

Coal Run joins North Branch Buffalo Creek 0.46 mi upstream of its mouth.

Tributaries
Coal Run has no named tributaries. However, it has a number of unnamed tributaries. The stream codes of these unnamed tributaries include 19039, 19041, and 19042.

Hydrology
Various tributaries to Coal Run are designated as impaired waterbodies. The cause of the impairment is nutrients and siltation, while the source is grazing-related agriculture. The total maximum daily load date is 2015. Streams in its watershed are also impacted by E. coli and thermal radiation. The stream and a number of others in Union County have been described as "not as clean as they should be".

In 2000, the load of sediment in Coal Run was 608838 lb and in 2008, it was 571464 lb. This equates to between 150 and 200 lb/acre per year. However, in the future, it could be reduced by 61.76 percent to 218504 lb per year. In 2000, row crops and streambank erosion were the largest contributors of sediment, contributing 289101 and 230144 lb, respectively. A total of 56742 lb came from hay and pastures, 9808 lb came from unpaved roads, 5639 lb came from low-density urban land, and 17404 lb came from other sources.

The nitrogen load of Coal Run in 2000 was 58691 lb, while in 2008, it was 58248 lb. This corresponds to between 15 and 20 lb/acre. In the future, the annual nitrogen load could be reduced by as much as 20.57 percent to 46264 lb.

In 2000, the phosphorus load of Coal Run was 2033 lb, while in 2008, it was 1999 lb. This equates to slightly less than 0.6 lb/acre per year. However, in the future, the phosphorus load could be reduced by 43.82 percent to 1123 lb per year.

Geography and geology
The elevation near the mouth of Coal Run is 538 ft above sea level. The elevation of the stream's source is between 740 and 760 ft above sea level.

There is no fencing or streambank stabilization in the watershed of Coal Run.

Watershed
The watershed of Coal Run has an area of 5.33 sqmi. The stream is entirely within the United States Geological Survey quadrangle of Mifflinburg. The watershed of the stream makes up 3 percent of the Buffalo Creek drainage basin. There are 13.4 mi of streams in the watershed, including 6.1 mi in agricultural land.

Agricultural land makes up 50 percent of the watershed of Coal Run and forested land makes up 40 percent. Impervious surface make up 3 percent of the watershed, though this could rise to 24 percent in the future. There are 21 acre of no-till conversions in the watershed.

The agricultural land in the watershed of Coal Run includes 974 acre of row crops and 969 acre of hay and pastures. A total of 346 acre of agricultural land are on slopes of more than 3 percent.

History
Coal Run was entered into the Geographic Names Information System on August 2, 1979. Its identifier in the Geographic Names Information System is 1172067.

A steel arch bridge carrying T-394 over Coal Run was built in 1984. It is 21.0 ft long and is located 1 mi north of Mifflinburg.

Biology
Wild trout naturally reproduce in Coal Run from its headwaters downstream to its mouth.

Vegetated buffer strips occur along 3.3 mi of streams in the watershed of Coal Run.

The pathogen load of Coal Run is 7.058 × 1015 organisms per month, though this could be reduced to 6.686 × 1015 organisms per month in the future. The largest contributors of pathogens are urban areas and farm animals (6.526 × 1015 and 5.503 × 1014 organisms per month, respectively). Septic systems and wildlife contribute 1.054 × 1012 and 4.451 × 1011 organisms per month, respectively.