Understanding controls on flow permanence in intermittent rivers to aid ecological research: integrating meteorology, geology and land cover

Abstract

Intermittent rivers, those channels that periodically cease to flow, constitute over half of the total discharge of the global river network and will likely increase in their extent owing to climatic shifts and/or water resources development. Burgeoning research on intermittent river ecology has documented the importance of the meteorologic, geologic and land-cover components of these ecosystems on structuring ecological communities, but mechanisms controlling flow permanence remain poorly understood. Here, we provide a framework of the meteorologic, geologic and land-cover controls on intermittent streamflow across different spatio-temporal scales and identify key research priorities to improve our understanding of intermittent systems so that we are better able to conserve, manage and protect them.

Flux dynamics at the groundwater-surface water interface in a tropical catchment

“…Increased extraction will cause a reduction of water entering the stream and hence will alter the stream flow regime and continuity, which consequently will impact the river and its surrounding wetland ecosystems (Costigan et al, 2015), particularly during base flow periods.…”

“…Our results may be more typical of tropical intermittent streams, especially in sandy coastal regions where aquifer transmissivity in high. The understanding of the flow permanence of intermittent river systems has been recognized to be important, but is still overlooked (Costigan et al, 2015). This example of discharge of groundwater to a stream in a tropical, agriculture-based catchment in Vietnam has pointed out that flow permanence in this environment is heavily dependent on the local climatic setting (i.e.…”

“…Notwithstanding this previous research, it is clear that our understanding of the hydrological processes controlling flow permanence and interactions between streamflow and aquifer recharge in intermittent river systems needs further improvement (Costigan et al, 2015). This knowledge gap is even more significant for tropical regions, where climate patterns are typically highly dynamic with distinct wet and dry seasons which strongly influence both surface flows and groundwater levels (Costigan et al, 2015;Nolte et al, 1997). The lack of information on intermittent stream dynamics is acute in these tropical areas, as rainfall data is missing or does not capture the high spatial variability because many catchments are ungauged, and no long-term hydrological datasets are available (Klemes, 1993).…”

“…Intermittent streams are inherently variable, with flows typically changing rapidly in response to rain events (Nolte et al, 1997), and can therefore be difficult to adequately characterize. Perennial streams have historically received greater attention than intermittent streams (Boulton and Suter, 1986;Williams, 1988), although recently more attention has been given to the importance of meteorological, geological, and land-cover controls on flows in intermittent streams (Costigan et al, 2015). Notwithstanding this previous research, it is clear that our understanding of the hydrological processes controlling flow permanence and interactions between streamflow and aquifer recharge in intermittent river systems needs further improvement (Costigan et al, 2015).…”

“…Perennial streams have historically received greater attention than intermittent streams (Boulton and Suter, 1986;Williams, 1988), although recently more attention has been given to the importance of meteorological, geological, and land-cover controls on flows in intermittent streams (Costigan et al, 2015). Notwithstanding this previous research, it is clear that our understanding of the hydrological processes controlling flow permanence and interactions between streamflow and aquifer recharge in intermittent river systems needs further improvement (Costigan et al, 2015). This knowledge gap is even more significant for tropical regions, where climate patterns are typically highly dynamic with distinct wet and dry seasons which strongly influence both surface flows and groundwater levels (Costigan et al, 2015;Nolte et al, 1997).…”