Flooding in ephemeral streams: incorporating transmission losses

Abstract

Streamflow in semi-arid lands commonly occurs in the form of flash floods in dry-bed ephemeral streams. The goal of this research was to couple hydrological and 2D hydraulic model treatments of channel transmission losses, in order to show the impact of not taking transmission losses on flood hazard mapping into consideration. For hydraulic modeling the reach that is located between flumes 2 and 1 in the Walnut Gulch Experimental Watershed was tested. Two hydraulics models were set up, the first does not incorporate channel transmission and the second was developed to take into account several hydrographs with transmission losses as boundary conditions. The error in volume and peak runoff rate between the observed and simulated data ranges was in the order of -4.5-34.4% for runoff volume and -16.4-9.6% for peak runoff rate. The computation output interval time in the hydraulic model was 60 s and the duration of flood inundation was 6.67 h. There are important differences in depth between the two flood maps, with 0.68 maximum and 0 m minimum. The importance of using models with the dynamic treatment of transmission losses is the ability to provide an improved estimate for flood hazard mapping.

Identifying Groundwater Recharge Sites through Environmental Stable Isotopes in an Alluvial Aquifer

“…The proximity of these groups to the streams may indicate that the streamflow represents one type of vertical recharge to the Calera aquifer, and this water can mix with other input flows in the aquifer. Besides, this group is close to the mountains, where the recharge from precipitation can appear, which is consistent with what was reported by Pacheco-Guerrero et al [30], McCallum et al [31], Shanafield and Cook [9], Goodrich et al [32], and Shentis and Rosenathal [33]. Nevertheless, different types of horizontal recharge can be present in the aquifer.…”

Water Flow Behavior and Storage Potential of the Semi-Arid Ephemeral River System in the Mara Basin of Kenya

“…Results from the field show that variability in storm-related flood pulses in the Sand River is dependent on the antecedent soil moisture in the alluvium deposits underlying the river bed; similar to the characteristics illustrated by Pacheco-Guerrero et al (2017) and Abdulrazzak and Sorman (2006). At the onset of a rainstorm, advancement of a surface flow wave downstream is limited by infiltration into the sand deposits.…”

“…A distinguishing feature of ephemeral rivers in semi-arid environments is the presence of a significant volume of water storage in the channel alluvium between runoff events (Mpala et al, 2016). The volume of flow events in such systems is influenced by transmission losses to groundwater storage beneath the channel bed (Abdulrazzak and Sorman, 2006;Shanafield and Cook, 2014;Pacheco-Guerrero et al, 2017). Rapid infiltration and percolation into the unsaturated alluvium during flow events ensures continuous water availability despite the rarity of flow events (Costa et al, 2013(Costa et al, , 2012Jarihani et al, 2015;Rodríguez-Burgueño et al, 2017).…”

Effects of Groundwater‐Surface Water Exchange Mechanism in the National Water Model over the Northern High Plains Aquifer, USA

“…Next, hydrologic extreme events of floods and droughts are identified from the historical record. For flood events, we hypothesize that the lack of a losing mechanism in the NWM will result in a higher intensity flood response forecast compared to the observed streamflow (Pinder and Sauer 1971; Sophocleous 2002; Pacheco‐Guerrero et al 2017). For drought conditions, by only considering the one‐way exchange, the NWM is incapable of modeling a stream losing water and entering the underlying aquifer.…”