scholarly journals Hydrologic evaluation of flood flows from a burned watershed

Author(s):  
A. W. Miller ◽  
E. J. Nelson
1999 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
E. James Nelson ◽  
A. Woodruff Miller ◽  
Eric Dixon

Forest fires often alter the balance between rainfall and resulting runoff of natural watersheds. This may result in flooding of the burned watershed at points down-stream. Such was the case for the Mud Canyon water-shed on New Mexico's Mescalero Apache Indian Reservation in 1996. While the summer storms that followed the spring fire had a magnitude to be expected every five years, the resulting flood flows were more on the order of a one hundred-year event. This 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 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.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2119
Author(s):  
Luís Mesquita David ◽  
Rita Fernandes de Carvalho

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s 0.5 m2/s. The results showed that a street with a 1.8% slope, 75 m1/3s−1 and a rectangular cross-section complies with the threshold 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1227 ◽  
Author(s):  
Russell Adams ◽  
Paul Quinn ◽  
Nick Barber ◽  
Sim Reaney

It is well known that soil, hillslopes, and watercourses in small catchments possess a degree of natural attenuation that affects both the shape of the outlet hydrograph and the transport of nutrients and sediments. The widespread adoption of Natural Based Solutions (NBS) practices in the headwaters of these catchments is expected to add additional attenuation primarily through increasing the amount of new storage available to accommodate flood flows. The actual type of NBS features used to add storage could include swales, ditches, and small ponds (acting as sediment traps). Here, recent data collected from monitored features (from the Demonstration Test Catchments project in the Newby Beck catchment (Eden) in northwest England) were used to provide first estimates of the percentages of the suspended sediment (SS) and total phosphorus (TP) loads that could be trapped by additional features. The Catchment Runoff Attenuation Flux Tool (CRAFT) was then used to model this catchment (Newby Beck) to investigate whether adding additional attenuation, along with the ability to trap and retain SS (and attached P), will have any effect on the flood peak and associated peak concentrations of SS and TP. The modelling tested the hypothesis that increasing the amount of new storage (thus adding attenuation capacity) in the catchment will have a beneficial effect. The model results implied that a small decrease of the order of 5–10% in the peak concentrations of SS and TP was observable after adding 2000 m3 to 8000 m3 of additional storage to the catchment.


2007 ◽  
Vol 21 (2) ◽  
pp. 114-126 ◽  
Author(s):  
H. Thomas ◽  
T. R. Nisbet
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