Abstract
Hydrological regimes, being strongly impacted by climate change, play a vital role in maintaining the integrity of aquatic river habitats. We investigated lag in hydrologic recovery following extreme meteorological drought events, and we also discussed its implications in the assessment of ecological environment flow. We used monthly anomalies of three specific hydrometeorological variables (precipitation, streamflow, and baseflow) to identify drought, while we used the Chapman–Maxwell method (the CM filter) with recession constant calculated from Automatic Baseflow Identification Technique (ABIT) to separate baseflow. Results showed that: (i) Compared to the default recession parameter (α = 0.925), the CM filter with the ABIT estimate (α = 0.984) separated baseflow more accurately. (ii) Hydrological drought, resulting from meteorological drought, reflected the duration and intensity of meteorological drought; namely, longer meteorological drought periods resulted in longer hydrological drought periods. Interestingly, the time lag in streamflow and baseflow indicated that aquatic ecosystem habitat recovery also lagged behind meteorological drought. (iii) Assessing environmental flow by quantifying drought provided greater detail on hydrological regimes compared to abrupt changes, such as the increased hydrological periods and the different environment flows obtained. Taken together, our results indicated that the hydrological response in streamflow and baseflow (e.g., the time lag and the precipitation recovery rate (Pr)) played a vital role in the assessment of environmental flow.
Highlights
Baseflow is defined as being either flow-derived from subsurface flow or other delayed water sources, which sustains streamflow during dry periods [1,2], playing a vital role in perennially maintaining aquatic habitats [3,4]
Applying the natural flow regime concept, e-flow has allowed us to bridge our understanding of the connection between hydrology and ecology [10], such as quantifying hydrologic alterations (e.g., Richter et al, 1996 [11]) and flow–ecology relationships (e.g., King et al, 2016 [12]), and to construct holistic frameworks to manage rivers that have been altered by flow regimes [13]
The objectives of this study were: (i) to separate baseflow using the Chapman–Maxwell method with recession constant estimated from the Automatic Baseflow Identification Technique (ABIT); (ii) to assess the response of hydrological drought characteristics to extreme meteorological drought; and (iii) to estimate the attribution of baseflow to e-flow in the Taoer River basin, China
Summary
Baseflow is defined as being either flow-derived from subsurface flow or other delayed water sources, which sustains streamflow during dry periods [1,2], playing a vital role in perennially maintaining aquatic habitats [3,4]. Alterations in hydrological regimes have led to the degradation of aquatic ecosystems [6] In this context, there is a growing need to assess hydrological response characteristics and estimate environmental flow (e-flow) to maintain the integrity of aquatic ecosystems. Its response to extreme meteorological events, will help us better understand interactions between flow regimes and habitats [5,16,17], which will help us to assess e-flow. The objectives of this study were: (i) to separate baseflow using the Chapman–Maxwell method (the CM filter) with recession constant estimated from the Automatic Baseflow Identification Technique (ABIT); (ii) to assess the response of hydrological drought characteristics to extreme meteorological drought; and (iii) to estimate the attribution of baseflow to e-flow in the Taoer River basin, China. This study explored the hydrological response to extreme meteorological drought and its implications in maintaining the integrity of aquatic ecosystems
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