Analysis of Available Retention Volume in Extinct Ponds – Case Study for Blanice River Catchment

The risk of increasing frequency and duration of dry periods has become much more discussed topic with respect to expected climate change. This can result in water scarcity for different purposes. Besides others, agriculture and river ecosystems can be mentioned as those which can suffer from droughts. The retention of the landscape is therefore still more accented. Increase of landscape retention capacity is considered as a good way to keep water in the landscape which can be then available during dry periods. Despite the most retention capacity consists in the soil, the volume of small water reservoirs must be considered as important in conditions of the Czech Republic. This results in increased demand for building new small water reservoirs spread in the landscape. However, there is a lack of suitable profiles for that due to relatively high population density in the Czech Republic. The restoration of extinct ponds is considered therefore as a good option for this purpose. The paper presents the results of GIS analysis of the volume of water which would be available in case of the restoration of extinct ponds in the catchment of the river Blanice (543 km2). For this purpose, detail elevation data were used to avoid unacceptable error in volume estimates due to the sizes of considered areas. The results of analyses show that there is considerable retention volume available which could be used either to improve hydrologic conditions in stream network or for agricultural use consisting mainly in irrigations. Additionally, the results were compared to discharge data for three profiles on main major stream channels. In general, the results show how the building of new small water reservoirs can be used to mitigate droughts.