Stormflow against streamflow - Effect of storage capacity in maintaining the pre-development flow regime
Abstract
The goal of Low Impact Development (LID) techniques, be it as an individual component or in a series, is to maintain the pre-development flow regime. However, this has been found to be challenging. The storage capacity is a function of the physical characteristics of LID techniques and it is easily quantifiable at the design phase. We investigated the storage capacities of three stormwater management train strategies (A, B and C) with increasing proportions of LID techniques arranged in series to explain their potential in maintaining the pre-development flow regime. The investigation was based on SWMM simulations for a seven-month (May to Nov 2012) period using calibrated parameters from an earlier study in the same site. The simulated stormflow from the drainage network associated with A, B and C was compared with the measured streamflow of neighboring watersheds (Aurajoki, Savijoki, and Kuninkoja), which are used as a reference for the pre-development state.
The increasing LID-provided storage capacity from A to B to C helped to lower the runoff coefficients during both summer (May to Aug) and autumn (Sept to Nov) periods. In addition, strategies B and C were able to resemble the runoff coefficients and flow dynamics of Kuninkoja and Savijoki during summer but not during autumn. When the sum of simulated stormflow and infiltration was compared against the measured streamflow, strategy C with the extensive coverage of vegetated LID techniques resembled the flow dynamics of the Kuninkoja watershed. This makes sense because also on natural watersheds the infiltrated water will eventually emerge as streamflow making the sum of stormflow and infiltration more representative of the watershed streamflow than stormflow alone. Compared to strategy C, strategies A and B have lower levels of evapotranspiration and consequently produce a higher proportion of either stormflow or infiltration. The results showed that the management train strategy that sets up the catchment environment favoring evapotranspiration has a higher potential to maintain the pre-development flow regime. The study suggests that the storage capacity of a LID technique is an important indicator for explaining its effect in controlling stormwater volume via infiltration and evapotranspiration and for maintaining the pre-development flow regime.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H12A..07K
- Keywords:
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- 0412 Biogeochemical kinetics and reaction modeling;
- BIOGEOSCIENCES;
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 1871 Surface water quality;
- HYDROLOGY;
- 1880 Water management;
- HYDROLOGY