KETERSEDIAAN DAN KEBUTUHAN AIR IRIGASI PADA RENCANA EMBUNG JETIS SURUH, DONOHARJO, NGAGLIK, SLEMAN, YOGYAKARTA

Sari

ABSTRACT 

Jetis Suruh area is located in the Donoharjo village, Ngaglik sub-district, Sleman regency, Yogyakarta Special District. The area has many the sources of water. Jetis Suruh area is planned to be built ponds irrigation, therefore, it is necessary to have the study / prediction of water availability and needs, so it can be the feasibility of the construction of these ponds. This Jetis Suruh ponds plans water balance was done by mainstay debit superposition and planting layout pattern plan of Jetis Suruh irrigation area. Mainstay debit for the needs of water service was taken 80%. The data which was needed for Mock’s model include semimonthly rain, evapotranspiration and the earth’s form maps. Data of the rain semimonthly was obtained from Kemput station rain, Angin-angin and Ledoknongko, Pakem, and Sleman. Evapotranspiration data was obtained by Penman’s method. Evapotranspiration calculation was done with computer helps and used MS Excel software. The data used was the data of Plunyon, Umbulharjo, Cangkringan, and Sleman meteorological stations. Then this data was used to calculate the mainstay debit. Prediction of water crop requirement was taken from the planting layout pattern plan on wetland area of 20 ha. Water balance was done by superposition of discharge mainstay and irrigation water requirements, so that deficit or surplus debit will be obtained. Based on the analysis of the water balance, surplus discharge varied from January of 6.00 l / second, rose to a peak in March of 60.00 l / second, down to a minimum in October at 2.00 l / second, then up again December at 9.00 l / second. Based on the results of the analysis, Jetis Suruh decent ponds plan can be constructed to accommodate discharge surplus and used in the dry season.

Keywords: Water Availability, Evapotranspiration, Planting Pattern