Sebaran Potensi Kekeringan Meteorologis di Daerah Aliran Sungai Bengawan Solo Bagian Hulu dan Upaya Penanggulangannya

Diah Auliyani; Nining Wahyuningrum

doi:10.22146/mgi.45534

Sebaran Potensi Kekeringan Meteorologis di Daerah Aliran Sungai Bengawan Solo Bagian Hulu dan Upaya Penanggulangannya

https://doi.org/10.22146/mgi.45534

Diah Auliyani^(1*), Nining Wahyuningrum⁽²⁾

(1) Balai Penelitian dan Pengembangan Teknologi Pengelolaan Daerah Aliran Sungai (BPPTPDAS), Jl. Ahmad Yani-Pabelan, Kartasura, Surakarta
(2) Balai Penelitian dan Pengembangan Teknologi Pengelolaan Daerah Aliran Sungai (BPPTPDAS), Jl. Ahmad Yani-Pabelan, Kartasura, Surakarta
(*) Corresponding Author

Abstract

Variabilitas hujan menyebabkan setiap wilayah berpotensi mengalami kekeringan. Waduk Gajah Mungkur telah berkontribusi menanggulangi kekeringan di Daerah Aliran Sungai (DAS) Bengawan Solo, namun pengelolaannya menghadapi ancaman pendangkalan akibat erosi. Tujuan penelitian ini untuk mengidentifikasi potensi kekeringan di DAS Bengawan Solo bagian hulu, dan mengidentifikasi penyebab pendangkalan Waduk Gajah Mungkur untuk upaya penanggulangannya. Standardized precipitation index (SPI) dari 93 stasiun hujan menunjukkan nilai bervariasi mulai -2,621 (amat sangat kering) hingga 7,689 (amat sangat basah). Kekeringan meteorologis yang terjadi berdurasi antara 1-7 bulan. Wonogiri merupakan kabupaten yang paling sering terpapar kekeringan. Karena ancaman pendangkalan, pembangunan Waduk Gajah Mungkur menjadi kurang efektif dalam menanggulangi kekeringan yang terjadi. Berdasarkan metode Universal Soil Loss Equation (USLE), erosi yang terjadi di hulu berperan terhadap pengurangan volume waduk. Beberapa upaya yang dapat dilakukan untuk menjaga daya tampung waduk adalah pengerukan secara berkala, revegetasi. dan pengolahan lahan yang tepat. Revegetasi dan pengolahan lahan yang tepat dapat dilakukan terutama di daerah dengan tingkat bahaya erosi berat dan sangat sangat berat. Pencegahan pendangkalan waduk ini diharapkan dapat menjaga kontinuitas ketersediaan sumber daya air.

Rainfall variability causes every region to experience drought. Gajah Mungkur Reservoir has contributed to the drought prevention in Bengawan Solo Watershed, but its management faces the threat of siltation for soil erosion. This study were aimed to identify potential droughts in the upstream Bengawan Solo Watershed and to identify the causes of siltation in the Gajah Mungkur Reservoir for its prevention efforts. Standardized precipitation index (SPI) of 93 rainfall stations varies from -2,621 (extremely drought) to 7,689 (extremely wet). The meteorological drought duration was between 1 to 7 month. Wonogiri is the most drought-exposed. For the threat of silting, the Gajah Mungkur Reservoir has become less effective in dealing with the drought. Based on the Universal Soil Loss Equation (USLE) method, soil erosion in the upstream contributes to the reduction in reservoir volume. Some efforts that should be done to maintain reservoir capacity are periodic dredging, revegetation. and proper land management. Revegetation and proper land management can be carried out in areas with severe and very severe erosion hazards. Prevention of silting of reservoirs is expected to maintain water resources availability.

Keywords

kekeringan, erosi, Gajah Mungkur, Wonogiri

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DOI: https://doi.org/10.22146/mgi.45534