Watershed Profile: Susquehanna River near Rockville, PA

Watershed Overview
The Susquehanna River begins at the outflow of Otsego Lake in Cooperstown, NY. The River flows 444 miles through New York, Pennsylvania and Maryland, before reaching its confluence with the Chesapeake Bay in Havre de Grace, MD. The monitoring station is in the Lower Susquehanna Subbasin near Rockville, PA. The station is downstream of the confluence with the Juniata River, but due to the lack of river mixing and location of the station on the left bank, its water quality is highly influenced by the mainstem.
Drainage Characteristics
  • Drainage Area (square miles): 23557.62
  • Total Stream Length (miles): 42746.0
  • Average Annual Flow at Station (NHD) (cfs): 36002.0
  • Population (2020): 2,381,396
Stream Classifications (Pennsylvania)
Designation Miles
Exceptional Value 1977.92
High-Quality Cold Water Fisheries 9304.49
High-Quality Trout Stocked Fisheries 79.30
Trout Stocked Fisheries 2426.92
Warm Water Fisheries 5655.59
Total 19444.22
Stream Classifications (New York)
Classification Use Miles
Class A Drinking Water Source 154.69
Class A (T) Drinking Water Source With Trout Population 33.94
Class A (TS) Drinking Water Source With Trout Spawning 24.49
Class AA Drinking Water Source 31.09
Class AA (T) Drinking Water Source With Trout Population 7.13
Class AA (TS) Drinking Water Source With Trout Spawning 3.08
Class B Contact Recreation (Not Drinking Water Source) 369.04
Class B (T) Contact Recreation With Trout Population 53.09
Class C Support Fisheries (Non-Contact) 7630.29
Class C (T) Support Fisheries, Non-Contact With Trout Population 1990.31
Class C (TS) Support Fisheries, Non-Contact With Trout Spawning 884.85
Class D Fishing, But Does Not Support Fish Propagation 8.98
Exempt Exempt 0.03
Total 11191.01
  • Land Use
  • Description Percentage
    Water 0.95
    Developed Open Space 4.85
    Low Urban 1.80
    Medium Urban 0.89
    High Urban 0.33
    Barren 0.26
    Deciduous Forest 47.07
    Coniferous Forest 2.81
    Mixed Forest 16.36
    Shrub Scrub 0.83
    Grassland Herbaceous 0.63
    Pasture/Hay 14.81
    Cropland 6.44
    Wetlands 1.97
Underlying Geology
Rock Type Percentage
Dolomite 1.40
Limestone 3.58
Quartzite 1.73
Sandstone 40.33
Shale 52.96
Recent Results
Sample Time 7/12/2024 7:00:00 PM
Temperature  (C) 26.14
Specific Conductivity  (mS/cm)
PH 7.89
Turbidity  (NTU+) 5.31
Dissolved Oxygen  (mg/L) 8.45
Dissolved Oxygen (last month of readings)
pH (last month of readings)
Specific Conductivity (last month of readings)
Temperature (last month of readings)
Turbidity (last month of readings)
Natural Gas
  • Natural Gas Pads 1946
  • Natural Gas Water Withdrawals 96
Public Water Supply Withdrawals
  • Groundwater 7163
  • Surface Water 377
NPDES Discharges
Description Count
Concentrated Animal Feeding Operation 199
Mining/Quarry 459
Stormwater 1259
Wastewater Treatment Plant/Sewage Treatment Plant 414
Other 1183
Stream Impairments
Source Category Miles
Acid Mine Drainage Aquatic Life 1816.50
Agriculture Aquatic Life 1757.60
Animal Feeding Operations Aquatic Life 7.25
Atmospheric Deposition Aquatic Life 428.50
Channelization Aquatic Life 50.20
Channel Erosion/Incision from Upstream Hydromodifications Aquatic Life 17.30
Coal Mining Aquatic Life 0.90
Combined Sewer Overflows Aquatic Life 14.20
Construction Aquatic Life 9.70
Crop Production Aquatic Life 191.20
Dam or Impoundment Aquatic Life 42.90
Erosion from Derelict Land Aquatic Life 17.44
Forest Roads Aquatic Life 1.90
Golf Courses Aquatic Life 11.30
Grazing in Riparian Zones Aquatic Life 190.20
Habitat Modification Aquatic Life 118.20
Highway/Road/Bridge Runoff Aquatic Life 274.80
Highways, Roads, Bridges Construction Aquatic Life 3.88
Impacts from Hydrostructure Flow Regulation Aquatic Life 21.20
Impervious Surface/Parking Lot Runoff Aquatic Life 23.10
Industrial Point Source Aquatic Life 32.70
Landfills Aquatic Life 1.81
Municipal Point Source Aquatic Life 52.20
Natural Sources Aquatic Life 14.70
On-Site Treatment Systems Aquatic Life 25.69
Removal of Vegetation Aquatic Life 98.60
Rural (Residential) Aquatic Life 120.00
Silviculture Aquatic Life 8.00
Site Clearance Aquatic Life 5.73
Source Unknown Aquatic Life 148.10
Streambank Modifications Aquatic Life 7.08
Surface Mining Aquatic Life 4.16
Urban Runoff/Storm Sewers Aquatic Life 181.80
Source Unknown Aquatic Life 18.00
Source Unknown Fish Consumption 519.50
Atmospheric Deposition Fish Consumption 698.00
Acid Mine Drainage Potable Water Supply 8.50
Source Unknown Potable Water Supply 1.80
Agriculture Recreational 230.00
Source Unknown Recreational 3001.20
Municipal Point Source Recreational 16.30
On-Site Treatment Systems Recreational 54.40
Urban Runoff/Storm Sewers Recreational 25.10
Combined Sewer Overflows Recreational 11.70