PROGRAM DESCRIPTION
The Susquehanna River Basin Commission implemented a five-year
nutrient-monitoring program in October 1984 to establish a database
for estimating nutrient and suspended sediment loads in the Susquehanna
River Basin. This monitoring effort, conducted as part of the Chesapeake
Bay Restoration Program, consisted of monthly base flow sampling and
periodic sampling throughout the high flow hydrograph for a minimum
of five storms per year.
Initially, 12 sampling sites were established. This sampling network
included a series of mainstem and major tributary sites, and a series
of sites located on smaller watersheds that had significant areas of
specific land use, or representative combinations of land uses. Collection
of data at stations on the mainstem and major tributaries was necessary
to enable accurate allocation of nutrient and suspended sediment loads
to the main river reaches and to major subbasins. Data were collected
for the Susquehanna River at Danville and Harrisburg, the West Branch
Susquehanna River at Lewisburg, the Juniata River at Newport, the Swatara
Creek near Hershey, the West Conewago Creek near Manchester, and the
Conestoga River at Conestoga, Pennsylvania, to confirm the Chesapeake
Bay Program watershed model load allocations and provide the basis for
refining the model outputs for these areas. Each site represented large
areas having significant differences and levels of complexity in terms
of geological setting and combinations of land uses.
The stations located on relatively small watersheds of varying geologic
settings provided a range of land uses or representative combinations
of land uses. The sites represent: (1) a total wilderness area--Stony
Creek at Water Tank Trail near Dauphin, Pa., (2) a sparsely populated
forest/cropland watershed with no areas of concentrated residential
development--Sherman Creek at Shermans Dale, Pa., (3) a small watershed
of intense suburban development throughout its headwaters area--Paxton
Creek near Penbrook, Pa., (4) a complex area that drains extensive cropland
with a number of fairly large reservoirs--Codorus Creek near York, Pa.,
and (5) a suburban and urban development--Codorus Creek at Pleasureville.
These watersheds were considered to be representative of many areas
throughout the basin and would provide detailed information for: (1)
refining the Bay watershed model, (2) identifying problems related to
specific land uses and combinations of land uses, and (3) identifying
future management actions in the area.
In 1987, an additional site was added on the Susquehanna River at Marietta,
Pa., to provide a better estimate of the nutrient and suspended sediment
loads transported by the Susquehanna River prior to entering the hydropower
reservoirs in the lower river. In 1989, another sampling site was established
on the Susquehanna River at Towanda, Pa., to provide an estimate of
nutrient and suspended sediment loads from New York State.
The initial five-year program was concluded at the end of December 1989,
and five of the twelve original sites were selected for continued long-term
monitoring. The Susquehanna River at Towanda, Danville and Marietta,
and the West Branch Susquehanna River at Lewisburg were selected to
provide long-term data to evaluate trends in nutrient and suspended
sediment transport from the major subbasin. The fifth site, the Conestoga
River at Conestoga was selected to provide long-term data from a major
tributary watershed with intensive agricultural activity and increasing
development. Implementation of Best Management Practices is also being
actively pursued. In October 1993, a sixth site, the Juniata River at
Newport was re-established for long-term monitoring.
In October of 2004, 13 additional sites were added to the monitoring
network as part of the Chesapeake Bay Program’s Non-tidal Monitoring
Network. This effort was conducted by the CBP Non-Tidal Water Quality
Workgroup based on the following objectives:
1. To measure and assess the actual nutrient and sediment concentration
and load reductions in the tributary strategy basins across the watershed.
2. To improve calibration and verification of partner’s watershed models.
3. To help assess the factors affecting nutrient and sediment distributions
and trends.
These new sites were chosen with the following priorities:
1. Outlets of major streams draining the tributary strategy basins
2. Areas within the tributary strategy basins that have the highest
nutrient delivery to the bay and tidal tributaries.
3. Represent the overall range of conditions in the Bay watershed. This
would include range of loads from different land cover types (urban,
agriculture, and forestland covers), physiographic/geologic setting,
and range of watershed sizes.
In October of 2005, four additional sites were
added as part of the same Non-tidal network. The current monitoring sites
for the SNAP are listed below.
Group A Sites (Long-term sites)
Susquehanna River at Towanda, Pa.
Susquehanna River at Danville, Pa.
Susquehanna River at Marietta, Pa.
West Branch Susquehanna River at
Lewisburg, Pa.
Juniata River at Newport, Pa.
Conestoga River at Conestoga, Pa.
Group B sites (Enhanced sites)
Chemung River at Chemung, N.Y.
Cohocton River near Campbell, N.Y.
Unadilla River at Rockdale, N.Y.
Susquehanna River at Smithboro, N.Y.
Susquehanna River at Conklin, N.Y.
Susquehanna near Wilkes-Barre, Pa.
West Branch Susquehanna River near Karthaus, Pa.
West Branch Susquehanna River near Jersey Shore, Pa.
Penns Creek at Penns Creek, Pa.
Raystown Branch Juniata River at Saxton, Pa.
Shermans Creek near Dromgold, Pa.
Conodoguinet Creek near Hogestown, Pa.
Swatara Creek near Hershey, Pa.
West Conewago Creek near Manchester, Pa.
Pequea Creek near Martic Forge, Pa.
Bald Eagle Creek near Castanea, Pa.
Octoraro Creek at Richardsmere, Md.
Data from the original sites are being used to compute annual loads of
nutrients and suspended sediment at each of the sites. The initial five-year
intensive sampling program provides baseline data that can be used to
evaluate changes in water quality as management practices are installed.
Data from the long-term monitoring sites also have been used for statistical
trend analysis.
