Kajian Kualitas Airtanah Bebas antara Sungai Kuning dan Sungai Tepus di Kecamatan Ngemplak, Yogyakata, Indonesia - Aris Sutardi; Slamet Suprayogi; Tjahyo Nugroho Adji (Fakultas Geografi, Universitas Gadjah Mada, 2017)
Pertumbuhan penduduk di Kabupaten Sleman telah menempatkan banyak tekanan pada sumber daya air. Perkembangan ini berkembang pesat ke daerah pedesaan termasuk Ngaglik, Ngemplak dan Kalasan Kecamatan. Oleh karena itu, studi tentang kualitas air di daerah ini penting. Daerah antara Sungai Kuning dan Sungai Tepus merupakan daerah yang ideal untuk melakukan penelitian ini saerah ini meliputi 3 kecamatan yaitu: Ngaglik, Ngemplak dan Kalasan. Dalam penelitian ini, parameter untuk menilai kualitas air terbatas pada 4 parameter: Nitrat, Nitrit, Amoniak dan Fosfat. Penelitian ini dilakukan pada tahun 2015, pengambilan sampel purposive dipilih untuk mengumpulkan besar sampel air tanah. Penggunaan lahan dan kegiatan lain yang dianggap dapat menyebabkan polusi air seperti pertanian, catel, dan limbah domestik. Sampel dianalisis di laboratorium untuk menentukan konsentrasi Nitrat, Nitrit, amoniak dan fosfat. Secara total, 23 sampel dikumpulkan. Selama kerja lapangan, tabel air diukur untuk menghasilkan peta flownet. Peta flownet ini akan digunakan untuk menganalisis potensi pencemaran air tanah. Hasil penelitian ini menunjukkan bahwa Nitrat, Nitrit, amoniak, dan fosfat yang bervariasi. Kontaminasi Nitrat dan Nitrit dalam air tanah masih di bawah standar sebesar 10 mg / L untuk Nitrat dan 0,06 mg / L untuk Nitrit sementara amoniak dan fosfat berada di atas standar sebesar 0,02 mg / L untuk amoniak dan 0,2 mg / L untuk fosfat. Tingginya jumlah amoniak ini disebabkan oleh kegiatan peternakan ayam sementara fosfat disebabkan oleh penggunaan pemupukan fosfat di daerah pertanian padi. Distribusi kualitas air tanah di daerah itu bervariasi berdasarkan penggunaan lahan, kegiatan orang dan aliran air tanah. Air tanah potensial pencemaran dilakukan berdasarkan aliran air tanah. Hasilnya menunjukkan bahwa daerah atas (utara) memiliki konsentrasi yang lebih rendah dari Nitrat, Nitrit, amoniak dan fosfat. Daerah pertengahan, di mana sebagian besar peternakan ayam dan pertanian berada, telah menjadi sumber pencemaran air. Population growth in Sleman regency have put a lot of pressure on water resources. This development is growing rapidly into the rural area including Ngaglik, Ngemplak and Kalasan Sub-district. Therefore, study about water quality in these area is important. The area between Kuning River and Tepus River is an ideal area to conduct this research since its cover 3 sub-districts: Ngaglik, Ngemplak and Kalasan. In this research, the parameter to assess water quality is limited to 4 parameters: Nitrate, Nitrite, Ammoniac and Phosphate. The study was conducted in 2015. Purposive sampling was selected to collect the groundwater sampels. Landuse and other people activities that can contribute to water pollution such as farming, catel, and domestic waste were considered. The samples were analysed in laboratory to define the concentration of Nitrate, Nitrite, ammoniac and phosphate. In total, 23 samples were collected. During fieldwork, the water table were measured to generate the flownet map. This flownet map will be used to analyse the groundwater pollution potential. The result of this research shows that the Nitrate, Nitrite, ammoniac, and phosphate were varies. The contamination of Nitrate and Nitrite in the groundwater is still below standard by 10 mg/L for Nitrate and 0,06 mg/L for Nitrite while ammoniac and phosphate were above standard by 0,02 mg/L for ammoniac and 0,2 mg/L for phosphate. These high number of ammoniac were caused by the chicken farming activities while phosphate were caused by the use of phosphate fertilization in the rice farming area. The distribution of groundwater quality in the area were varies based on the landuse, people activities and groundwater flow. The groundwater potential pollution were conducted based on the groundwater flow. The result show that the upper area (north) has lower concentration of Nitrate, Nitrite, ammoniac and phosphate. The mid area, where most of the chicken farm and rice farm are located, has become the sources of the water pollution.