Using GIS to aid in Modeling the

Susquehanna River BasinPresented by Monica Wedo

December 5, 2000

Presentation OverviewBackground on the Susquehanna River Basin

Project goals and motivation

Procedure

Results

Future work

Susquehanna River BasinArea: 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 RiverFlows 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 RiverPesticides in wells and stream water Radon in the ground waterAcid mine drainageAgricultural Runoff

Organizations Interested in Protecting Basin Health

Susquehanna River Basin Commission (SRBC)

National Water Quality Assessment Program (NAWQA)

Project Goals and Motivation

USE GIS toIncorporate flow data for varying flow conditions into ArcViewDetermine the upstream distance of each gage from the point where the Susquehanna River meets the Chesapeake BayComplete 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 ArcInfoCreated 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 NetworkUsed 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 WorkDetermine 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