Bio-inspired heuristic dynamic programming for high-precision real-time flow control in a multi-tributary river system

Increasing areas of aquaculture ponds and reservoirs reshape runoff coefficients: evidence from a subtropical catchment, China

Detention pond is a key storm water management measure employed both to attenuate surface runoff and to regulate depression storage, yet the effects of aquaculture ponds and reservoirs on runoff coefficient are not well quantified in a subtropical humid monsoon climate zone, China. Here, a set of six subcatchments ranging in size from 0.7 hm² to 10,000 hm² were evaluated over the 2011-2015 period. (i) The annual average runoff coefficient differed with different subcatchments due to the spatial heterogeneity of landscape patterns, while the event-based runoff coefficient under the same catchment showed a decreasing trend with increasing rainfall intensity. (ii) The annual average and event-based runoff coefficients initially increased and then decreased with an increase in the area ratio of aquaculture ponds and reservoirs. The critical area ratio of aquaculture ponds and reservoirs for the maximum runoff coefficient in annual, light, and moderate rainfall intensity was about 4%; but this value would be transferred forward to the position of < 4% under the intensity of heavy rain, rainstorms, and heavy rainstorms. (iii) All runoff coefficients decreased with increasing forestland but increased with increasing paddy fields, and the decreasing rate was greater than the increasing rate. The trends of runoff coefficient for the annual and event-based rainfall are opposite between river development coefficient and watershed shape coefficient. The results provide underlying insights for decision-makers in aquaculture land-use planning and the sustainable utilization of water resources in the upstream and downstream systems of a catchment.