Pengembangan Konsep Zero Runoff System (ZROS) untuk Optimalisasi Kadar Air Tanah pada Lahan Perkebunan Non Irigasi

Abstract

Abstract
On non-irrigated farming land, soil water content was difficult to be maintained in field capacity condition. Zero runoff system (ZROS) attempted to utilize runoff and to convert it to backup soil water content using permeation structures. The objectives of this research was to analyze the changing of soil water content before and after ZROS had been applied and to calculate ZROS effectivity towards infiltrating rainfall. In this research, permeation structures in the research field was usingsilt pit and collector canal. The changing of soil water content before and after ZROS application was calculated by water balance model in the
rooting zone. The simulation result showed that after ZROS had been applied, the decreasing of soil water content in research field were ranging from -0.001 to -0.009 m3/m3, while before ZROS had been applied
it were ranging from -0.01 to -0.024 m3/m3. Besides that, ZROS also capable to increase soil water content in research field for 25.57%. The increasing of this soil water content was caused by ZROS ability that can
hold and infiltrate 51.04% from total rainfall occurredeffectively.
Keywords: permeation structure, runoff, soil water content, water balance model, zero runoff system

Abstrak
Pada lahan non irigasi, kadar air tanah sulit dipertahankan pada kondisi kapasitas lapang dan sangat tergantung pada curah hujan. Zero runoff system (ZROS) berupaya memanfaatkan limpasan permukaan dan mengkonversinya menjadi cadangan air tanahdengan menggunakan bangunan resapan. Penelitian ini bertujuan menganalisis perubahan kadar air tanah sebelum dan sesudah penerapan ZROS serta menghitung efektifitas ZROS dalam meresapkan air hujan. Pada penelitian ini, bangunan resapan yang digunakan berupa rorak dan saluran pengumpul. Perubahan kadar air tanah yang terjadi sebelum dan sesudah diterapkan ZROS dihitung menggunakan model kesetimbangan air di dalam zona perakaran tanaman. Hasil simulasi menunjukkan bahwa setelah diterapkan ZROS, penurunan perubahan kadar air tanah berada pada kisaran -0.001 sampai -0.009 m3/m3 sedangkan sebelum ZROS sebesar -0.01 sampai -0.024 m3/m3. Selain itu, ZROS juga mampu meningkatkan kadar air tanah di lokasi penelitian sebesar 25.57%. Kenaikan kadar air tanah ini disebabkan oleh kemampuan ZROS yang secara efektif menampung dan meresapakan 51.04% dari curah hujan yang terjadi selama periode pengukuran
Kata Kunci : bangunan resapan, kadar air tanah, limpasan permukaan, model kesetimbangan air, zero runoff system.

Diterima: 07 Mei 2014; Disetujui: 19 Agustus 2014