Methods to Evaluate Floods on a Burned Watershed

Methods to Evaluate Floods on a Burned Watershed

A.W. Miller E.J. Nelson 

Department of Civil & Environmental Engineering, Brigham Young University, USA

Page: 
376-388
|
DOI: 
https://doi.org/10.2495/SAFE-V1-N4-376-388
Received: 
N/A
|
Accepted: 
N/A
|
Published: 
31 December 2011
| Citation

OPEN ACCESS

Abstract: 

This updated study focused on the methodologies, tools, and applications used to evaluate the hydrologic runoff potential of a burned watershed when few variables were actually measured. Forest fires often alter the balance between rainfall and the resulting runoff from natural watersheds. This may result in flooding from the burned watershed at locations downstream. Such was the case for the Mud Canyon watershed on New Mexico’s Mescalero Apache Indian Reservation. In the spring, a fire burned approximately 42% of the watershed. Subsequent storms during the summer caused flows in Mud Canyon that led to flooding downstream at the town of Mescalero. The flooding was likely the result of inadequate remediation, neither human nor natural, during the months between the fire and the storms. While the summer storms that followed the spring fire had an updated magnitude to be expected every 10 years, the resulting updated flooding was more on the order of a 500-year event. A purpose of this study was to determine the amount of rainfall that produced the estimated flood flows. This result could then be used to determine the degree to which the burned portion of the watershed caused the flooding. The Burned Area Emergency Rehabilitation (BAER) Plan concluded that there was not a serious threat of flooding, based on the fact that the soils in the watershed were well-drained and not hydrophobic. The paper concludes that the loss of ground cover, particularly for relatively steep watersheds, should be seriously considered when evaluating the potential for flooding on a burned watershed. The methods used for this updated hydrologic analysis of Mud Canyon, as outlined in this paper, are applicable for future analyses of burned watersheds to determine the extent to which loss of ground cover contributes to increased flood flows.

Keywords: 

burned watershed, curve number, DEM, flooding, intensity-duration-frequency, return period, roughness

  References

[1] Department of the Interior, Southern States Burned Area Emergency Rehabilita-tion (BAER) Team, Chino Well Fire Burned Area Emergency Rehabilitation Plan, United States Department of the Interior, Bureau of Indian Affairs, Mescalero Agency, 1996.

[2] Waltemeyer, S.D., Analysis of the magnitude and frequency of peak discharge and maximum observed peak discharge in New Mexico, U.S. Geological Survey with the New Mexico Department of Transportation, Scientifi c Investigations Report 2008-5119, pp. 1–105, 2008.

[3] Miller, J.F., Frederick, R.H. & Tracey, R.J., Precipitation-frequency atlas of western United States, NOAA Atlas 2, IV-New Mexico, 1973.

[4] CEWRC-HEC, HEC-1 Flood Hydrograph Package User’s Manual, Hydrologic Engineering Center, CPD-1A, 1990.

[5] Soil Conservation Service, SCS National Engineering Handbook, Sec. 4, Hydrology, USDA, 1972.

[6] Nelson, E.J., Jones, N.L. & Miller, A.W., An algorithm for precise drainage basin delin-eation, Journal of Hydraulic Engineering, 120(3), pp. 298–312, 1994. doi:http://dx.doi.

org/10.1061/(ASCE)0733-9429(1994)120:3(298)

[7] Peucher, T.K. & Douglas, D.M., Detection of surface-specifi c points by local parallel processing of discrete terrain elevation data, Computer Graphics and Image Processing, Vol. 4, pp. 375–387, 1975. doi:http://dx.doi.org/10.1016/0146-664X(75)90005-2

[8] Martz, L.W. & Garbrecht, J., Numerical defi nition of drainage network and subcatchment areas from digital elevation models, Computers and Geosciences, 18(6), pp. 747–761, 1992. doi:http://dx.doi.org/10.1016/0098-3004(92)90007-E

[9] Department of Commerce, Climatological Data, New Mexico, National Oceanic and Atmospheric Administration, 1996.

[10] Leopold, L.B., Characteristics of heavy rainfall in New Mexico and Arizona, Proceedings, ASCE, pp. 837–892, 1943.

[11] Riverside County Flood Control and Water Conservation District, The application of synthetic unit hydrographs to drainage basins in the Riverside County District, Riverside County, CA, 1963.

[12] Zwolinski, M.J., Effects of fi re on water infi ltration rates in a Ponderosa Pine stand, Hydrology and Water Resources in Arizona and the Southwest, 1, pp. 107–112, 1971.

[13] Maidment, D., Operational Infi ltration Models, Handbook of Hydrology, McGrawHill, New York, p. 5.28, 1993.

[14] Wanielista, M., Kersten, R. & Eaglin, R., Hydrology: Water Quantity and Quality Control, John Wiley & Sons, New York, pp. 158, 1997.

[15] Campbell, R.E., Baker Jr., M.B., Folliot, P.F., Larson, F.R. & Avery, C.C., Wildfi re effects on a Ponderosa Pine ecosystem: an Arizona case study, USDA Forest Service Research Paper, RM-191, pp. 1–12, 1977.

[16] Brown, J.A.H., Hydrologic effects of a bushfi re in a catchment in south-eastern New South Wales, Journal of Hydrology, 15(1), pp.77–96, 1972. doi:http://dx.doi. org/10.1016/0022-1694(72)90077-7

[17] Lavabre, J., Torres, D.S. & Cernesson, F., Changes in the hydrological response of a small Mediterranean basin a year after a wildfire, Journal of Hydrology, 142, pp. 

273–299, 1993. doi:http://dx.doi.org/10.1016/0022-1694(93)90014-Z

[18] Chow, V.T., Hydrology of Forest Lands and Rangelands, Handbook of Applied Hydrology, McGraw-Hill, New York, pp. 22.31–22.38, 1964.