Abstract:
Environmental restoration of spring Catchment Area (CA) and groundwater Recharge Area (RA) was almost impossible to achieve without any integrated environmental management effort in a long term periode because it was related to various stakeholder’s interests. Protecting water resources policy in Southern part of Merapi Volcano Slope using CA and RA concepts became the ultimate goal of this study. Methods were used comprehensive and holistic environmental conservation approaches, involving abiotic, biotic, and cultural aspects to recover the environmental function through restoration of CA and RA areas. Spring CA and groundwater RA perimeter delineation were implemented as unit of study for recovery and enhancement of CA and RA land cover precentage as well as for increasing the spring discharge and groundwater volume. Increasing the spring’s discharge would lead to addition of paddy field areas that could be irrigated and enhancing the river discahrges to add up water availability of river region or watershed areas, while enhancement of CA and RA land cover precentage would result in increasing the infiltration capacity as well as groundwater storage including shallow and deep groundwater storages. Shortterm result of site visit showed there was a river infrastructure development (SABO Dam) for lahar retention underconstruction. Land cover enhancement was dominated by natural plant of Soga (Accasia Decurens) and man-planted Sengon (Albizia Falcataria). In between, mixed crops were also planted by local people thus the landuse was identified as mixed garden. For the time being, the land cover enhancement has not yet recover the hydrological condition in the study area, which should be indicated by emerging springs and increasing river discharges, thus water scarcity still became the main issue for some rivers whose upstream poured out from southern part of Merapi volcano slope, such as, Opak river and Sriwil river from Kinahrejo-Pangukrejo Villages, Opak river from Kepuharjo Village and Gendol river from Kalitengah and Srunen Villages. The waterflow of Opak river were contributed from Nduwet (Sanga) and Cakran springs in Kalisongo Village and the waterflow of Sriwil river were from Umbul Celeng spring. Meanwhile, the waterflow from those springs (Nduwet/Sanga, Umbul Sodokan, Cakran, Pandan, Umbul Celeng) were utilized by local people for paddy irrigation, fish ponds, and daily domestic needs. The depth of shallow groundwater in lahar-covered area was more than 20 m (sea level), such as, in Plosokerep (Kepuharjo), Karanggeneng (Umbulharjo), Jetisumur (Glagaharjo), Sidorejo (Hargibinangun), wonorejo (Purwobinangun), Bening and Kratuan (Girikerto), and Gondoarum (Turi). Special areas were villages of Cangkringan and part of Pakem Districts which then fulfilled the fresh water needs using artesian well whose depth was up to 150 m (sea level). The excessive flow from springs and groundwater would be stored in Opak, Sriwil, Tepus, and Gendol rivers. Different with cangkringan and Pakem Districts in Hargobinangun, Purwobinangun, Girikerto, and Turi Districts the waterflows was dominated by spring and seepages which is emerging in river banks and vallies, such as, Sidorejo, Wonorejo, Kratuan, pelem, Jineman, Kuncen and Gondoarum villages. Starting From Boyong, Tangkil, Degong, and Sempor river dams the waterflows were channelized as gravitation flowdown into lowland to create wetland rice is called “sawah”. Study on planning and designing the open channel flow from springs (Cangkringan and Pakem Districts) and rivers (Turi District) channelized to the channel network using site selection method to create a kind of Mataram Channel (from Progo to Opak rivers) would be the target of next study step.
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