Author(s): Haryo Jayeng Rono, Joko Sujono, Rachmad Jayadi, Intan Supraba
Linked Author(s): Intan Supraba
Keywords: Bioengineering for land reclamation, water balance, water quality, water system
Abstract: Coastal area in Srandakan and Saden districts of Bantul Regency, Daerah Istimewa Yogyakarta (DIY) has a great potential of land resources. However, the region became an arid and hot coastal area causing land degradation. Bioengineering method for land reclamation by planting Cemara Udang (Casuarina equisetifolia) results in the change of microclimate. The main indicators are reduction of temperature, wind speed, and land surface evaporation. Pine can grow well if the root system is able to obtain fresh groundwater. Thus, the main factor to guarantee the sustainability of this reclamation is water availability. During the dry season, the groundwater salinity increased as the groundwater level decreased, and results in less optimal of the pine growth. Therefore, this study is intended to analyze water balance, water quality, and efforts to reduce water deficits. The efforts to reduce water deficits, and to maintain groundwater elevation were simulated using 3 different alternatives. The alternative design I is optimizing water recharge, the alternative design II is optimizing water recharge and reducing groundwater pumping, and the alternative design III is optimizing water recharge, reducing groundwater pumping, and managing crop schedule. Results showed that roots of pine are able to obtain fresh groundwater if the groundwater level is at elevation +4. 00 m or higher. During the period of study, the average ground water elevation was +3. 93 m. Alternative design I reduced the deficit by 9. 12% and maintained average ground water level at elevation + 3. 98 m, alternative design II reduced the deficit by 69. 91% and maintained average ground water level at elevation + 4. 35 m, and alternative design III reduced the deficit by 75. 21 % and maintained average ground water level at elevation + 4. 39 m. Design III as the best alternative needs extra water for every 170 m long channel by 4. 94 l/s
Year: 2017