A framework for evaluating regional hydrologic sensitivity to climate change using archetypal watershed modeling

Abstract

Abstract. The current study focuses on the development of a regional framework to evaluate hydrologic and sediment sensitivity, at various stages of urban development, due to predicted future climate variability. We develop archetypal watersheds, which are regional representations of observed physiographic features (i.e., geomorphology, land cover patterns, etc.) with a synthetic basin size and reach network. Each of the three regional archetypes (urban, vegetated and mixed urban/vegetated land covers) simulates satisfactory regional hydrologic and sediment behavior compared to historical observations prior to a climate sensitivity analysis. Climate scenarios considered a range of increasing temperatures, as estimated by the IPCC, and precipitation variability based on historical observations and expectations. Archetypal watersheds are modeled using the Environmental Protection Agency's Hydrologic Simulation Program-Fortran model (EPA HSPF) and relative changes to streamflow and sediment flux are evaluated. Results indicate that the variability and extent of vegetation play a key role in watershed sensitivity to predicted climate change. Temperature increase alone causes a decrease in annual flow and an increase in sediment flux within the vegetated archetypal watershed only, and these effects are partially mitigated by the presence of impervious surfaces within the urban and mixed archetypal watersheds. Depending on the extent of precipitation variability, urban and moderately urban systems can expect the largest alteration in flow regimes where high-flow events increase in frequency and magnitude. As a result, enhanced wash-off of suspended sediments from available pervious surfaces is expected.

Study on Variations in Climatic Variables and Their Influence on Runoff in the Manas River Basin, China

“…Although using the GCM as the model input, the uncertainty of the input data was not considered in this research. Lopez, et al [12] studied the sensitivity difference between the response of runoff and sediment to climate change under three underlying surfaces; vegetation, urban, and mixed-type cover, within a regional framework. Wang, et al [13] studied the response of runoff to climate change using a two-parameter hydrological model and analyzed the variations and correlation historical hydrological and climatic variables.…”

A Combined Method for Estimating Continuous Runoff by Parameter Transfer and Drainage Area Ratio Method in Ungauged Catchments

“…Together, these modules can represent the hydrologic cycle in a watershed. Different modules are activated for various simulation requirements [26,27]. In this study, various model parameters were calibrated manually.…”

Impacts of Projected Climate Changes on Streamflow and Sediment Transport for Three Snowmelt‐Dominated Rivers in the Interior Pacific Northwest

“…increased turbidity) that leads to increasing costs of drinking water treatment; binding of nutrients, metals, and other pollutants to the sediment particles; and infilling of spawning gravels and smothering of eggs of vulnerable fish species such as salmonids. Climate change can potentially lead to an increase in flood events that flush large quantities of suspended sediment into river systems, especially in combination with deforestation and other direct human impacts, which have been found to be more significant than climate in determining sediment fluxes (Ward et al, 2009;Naik and Jay, 2011;Gao et al, 2013;Lopez et al, 2013;Ma et al, 2013). Although these processes are not directly simulated by SWAT, rivers dynamically adjust their channels and floodplains to inputs of water and sediment, so changes in these driving variables may also affect geomorphic characteristics such as channel geometry and planform.…”