Modelling optimal water retention in hydrogenic habitats using LIDAR laser data.

Degradation of hydrogenic habitats in climate change increased rapidly. It is important that we take actions to stop this process. Solution is to increase efficiency of water usage by ecosystems - especially water based ones. Building devices for delaying surface water runoff - like locks and dams - should improve hydrogenic habitats conditions and allow surrounding ecosystems use rainwater more efficient. Modelling of small retention in forests is an important aspect in decision making schema. Aim of this paper is to point optimal solutions for height and placement of devices which delay surface water runoff to set necessary water table level for renaturalization and maintenance of degrading natural habitats. Data used for analyses were acquired in the Polanów Forest Inspectorate in West Pomeranian voivodeship because of the topography diversification and the drainage infrastructure presence. There were three research plots selected based on decreased stability of habitats and historic data stated that there were natural water reservoirs, which were drained in past. Based on 2012 LiDAR (Light Detection and Ranging) point cloud the digital terrain model (DTM) was built. Water outflow points - melioration canals - were identified and analysed for optimal device localization. In following part of research specific data for each hydrogenic habitat were used to model height of devices which delay surface water runoff. Optimal level of device and area covered by water were set for each site separately. The results were handed over to the investor for implementation, then the compliance of the assumptions of the simulation of raising the water table with the as-built field measurements was checked. Study shows that it is possible to use laser technology to optimize location and height of devices which delay surface water runoff what allows to restore degraded hydrogenic habitats. Presented method supports small local retention what increases limited water resources in this region, decreases rapid runoff of surface water which causes frequent floods. Proposed method of modelling the location and height of the dams or locks is universal. Even though results are unique for each object the method is possible to be applied to every other situation.