1. CEE 6440 GIS in WATER RESOURCES
Program to Generate Stream Network Width Function By
Anurag Nayak

2. Channel Network Width Functionx x
The number of channels at a distance x from the outlet
Source:

3. Use of width function in hydrology:
Width function based instantaneous unit hydrograph generation
RIGON et al.:Getting the Rescaled Width Function and the Derived WGIUH
To model the response of stream network.

4. CALCULATION OF NETWORK RESPONSE FUNCTION FROM NWF
NRF is calculated from the NWF and a routing function using velocity (A m/s) and diffusion (D m2/s) coefficients
Routing
Function
(parameters A and D)
LINKS
RESPONSE = *
DISTANCE
TIME
NWF
NRF
University college London, Department of Geomatic Engineering

5. CALCULATION OF PREDICTED RIVER FLOWS
Hydrological model used to produce ‘generated runoff’ from precipitation, where ‘generated runoff’ is that portion of precipitation which enters the channel network *
FLOW =
RESPONSE
RUNOFF
TIME
TIME
TIME
PREDICTED
FLOW
NRF
RUNOFF

6. Stream Network of Logan River

7. Input Files: 1: Link Number 2: Start Point Number 3: End Point Number
4: DSLink Number
5&6: USLink Number
7: Order of Link
8: Monitoring Point Identifier
1: X Coordinate
2: Y Coordinate
3: Distance along channels to DS Termial link
4: Elevation
5: Contributing Area

8. Programming Logic Read input files tree.dat and coord.dat.
Calculate the stream length of each link.
Calculate downstream distance to the outlet.
DSLength(Link) = Length(DSLink)+ DSLength(DSLink)
Width Function at any distance x is defined as the number of links for which
DSLength(Link) < x < DSLength(Link) + Length(Link)

9. Generated Width Function for Logan River

10. Stream Network of Bear River

11. Generated Width Function for Bear River WaterShed

12. Future Possibilities
Can be added as a tool in TauDEM to analyze stream network response.

13. QUESTIONS