Using GIS to aid in Modeling the Susquehanna River Basin Presented by Monica Wedo December 5, 2000

Presentation Overview Background on the Susquehanna River Basin Project goals and motivation Procedure Results Future work

Susquehanna River Basin Area: 27,500 sq. miles Comprised of 6 subbasins 43% of Chesapeake Bay’s drainage area Population of over 3.8 million people Flood proned area

Susquehanna River Flows 444 miles from Cooperstown, NY to Harve de Grace, MD, where the river meets the Chesapeake Bay The average daily flow of the Susquehanna is 22 billion gallons per day. It is the largest tributary of the bay, providing 90 of the fresh water inflow to the upper half of the bay and 50 overall. In fact, the Chesapeake Bay is nothing more than the submerged area of what was once the lower Susquehanna River some 10,000 years ago.

Source of Basin Impairment Excess nitrate in the Susquehanna River Pesticides in wells and stream water Radon in the ground water Acid mine drainage Agricultural Runoff

Organizations Interested in Protecting Basin Health Susquehanna River Basin Commission (SRBC) National Water Quality Assessment Program (NAWQA)

Project Goals and Motivation USE GIS to Incorporate flow data for varying flow conditions into ArcView Determine the upstream distance of each gage from the point where the Susquehanna River meets the Chesapeake Bay Complete the flow network for this river system using ArcInfo Motivation??

Graphing Flow vs. Distance rf1 HUC Region 5 State County Gage

Gathering Flow Data Low Flow (cfs) - 9/09/95 Avg. Flow (cfs) - 3/24/95 High flow (cfs) - 3/26/94

Measuring Stream Distance Used Identify Tool to obtain length in meters of each reach Estimated distance from the Chesapeake Bay entrance to each gage by summing all downstream reaches Gathered distances for both the Susquehanna and the West Branch Susquehanna Rivers

Result: Plot of Flow vs. Distance for three flow conditions

Completing the Stream Network Created a new theme by selecting all rivers and streams with USGS gages

Using ArcInfo Created a new feature dataset with the gage and Susquehanna River shapefiles Added 3 outlets for where flow terminates into the Chesapeake Bay Created a geometric network

Editing the Network Used the trace upstream function in the utility network analyst Used the editor toolbar to connect gaps in stream network Snapped the stream gages to the network

Result: Complete Flow Network

Future Work Determine which stream connects to the lone reach and complete the flow network Add contributing area data for each of the 34 gages into the attribute table Begin to investigate the vast array of pollution data online