Impact of Changing Climate and Land Cover on Flood Magnitudes in the Delaware River Basin, USA

Abstract

Changing climate and land cover are expected to impact flood hydrology in the Delaware River Basin over the 21st Century. HEC‐HMS models (U.S. Army Corps of Engineers Hydrologic Engineering Center‐Hydrologic Modeling System) were developed for five case study watersheds selected to represent a range of scale, soil types, climate, and land cover. Model results indicate that climate change alone could affect peak flood discharges by −6% to +58% a wide range that reflects regional variation in projected rainfall and snowmelt and local watershed conditions. Land cover changes could increase peak flood discharges up to 10% in four of the five watersheds. In those watersheds, the combination of climate and land cover change increase modeled peak flood discharges by up to 66% and runoff volumes by up to 44%. Precipitation projections are a key source of uncertainty, but there is a high likelihood of greater precipitation falling on a more urbanized landscape that produces larger floods. The influence of climate and land cover changes on flood hydrology for the modeled watersheds varies according to future time period, climate scenario, watershed land cover and soil conditions, and flood frequency. The impacts of climate change alone are typically greater than land cover change but there is substantial geographic variation, with urbanization the greater influence on some small, developing watersheds.

Coupling of Cellular Automata Urban Growth Model and HEC-HMS to Predict Future Flood Extents in the Upper Klang Ampang Catchment

“…November, 2015, there is less increase (11%) in predicted future peak discharge since the rainfall is more distributed over Klang River catchment which has less urban growth (saturated urban development). The results indicate the ability of HEC-HMS tightly coupled with the CA model to predict the increase in flood extents for increase urbanization as also shown by other study [44], [45].…”

Global-scale characterization of streamflow extremes

“…The dominant land cover within a catchment is expected to play a significant role in the runoff generation process and thus the unit peak discharge, as confirmed by several studies (Ahn & Merwade, 2016;Ashraf M. & Yasushi, 2008;Kiran et al, 2017;Woltemade et al, 2020). The change in land use and land cover alters the geomorphology of the catchment, eventually affecting floods (Cao et al, 2020).…”

Prototyping a Methodology for Long-Term (1680–2100) Historical-to-Future Landscape Modeling for the Conterminous United States

“…The timing of this drought precludes the use of direct Landsat observations for characterizing historical LULC. Historical change in anthropogenic land use has had strong impacts on water resources in the region, while anticipated future land use and climate change are likely to further stress those resources [28]. The long-term landscape time series developed here will be used to explore historical relationships between land use, water use, and drought, as well as facilitate future water resource planning in the region.…”