Pola distribusi TDS di tiga lokasi sungai segmen Cimahi-Bandung Utara dan perkiraan sumbernya (TDS distribution at three river segments Cimahi - North Bandung

This is the final version of master thesis from Sri Aditya. Supervisor: Dasapta Erwin Irawan.

<< Indonesian version >> Variasi harian data kualitas air dapat dianalisis untuk mengetahui proses yang terjadipada air sungai itu sendiri juga interaksinya dengan air tanah, khusus pada zonahyporheic. Observasi dilakukan di tiga lokasi anak Sungai Cikapundung di tahun2017 (periode Maret-November 2017). Pengukuran dilakukan pada tiga lokasidi DAS S. Cikapundung (diurutkan dari utara-selatan): S. Ciawitali lokasi CurugPanganten (CP) dan Grand Royal Pancanaka (GRP), S. Cibeureum lokasi PondokHijau Indah (PHI). Tata guna lahan berevolusi dari lahan terbuka berupa hutan danlahan perkebunan/pertanian di lokasi CP dan GRP, ke perumahan di PHI. Sungai diketiga lokasi itu menjadi muara dari saluran-saluran air yang melewati kawasan ditepi kiri dan kanannya.Pengukuran debit (meter/detik), temperatur air sungai (derajat Celcius), temperaturudara (derajat Celcius), dan TDS (total dissolved solids) (ppm).Pengukurandilakukan dengan alat portabel merk Lutron, masing-masing dengan ketelitian 0.01pada masing-masing satuan yang berkaitan. Pengukuran dilakukan empat kali dimasing-masing lokasi: pukul 10.00, 12.00, 14.00, dan 16.00. Data kemudiandianalisis menggunakan piranti lunakopen sourceR untuk tekniktime series.Hasil pengukuran di ketiga lokasi tersebut menunjukkan variasi mingguan danbulanan. Untuk variasi minggu, nilai TDS naik mulai hari Jumat dan turun pada hariSenin. Lokasi yang paling konsisten menunjukkan gejala ini adalah PHI. Variasibulanan menunjukkan peningkatan di bulan Juni dan turun di bulan Juli. Pola initerjadi di tiga lokasi tersebut. Pada titik ini, kami berpendapat bahwa pola tersebutdiduga berkaitan dengan aktivitas manusia yang meningkat di akhir minggu. Untukpola bulanan, ada indikasi bahwa peningkatan TDS bersamaan dengan liburanLebaran 2017. Dugaan tersebut perlu diklarifikasi lebih lanjut dengan pengukurankandungan nutrien (nitrat, nitrit, fosfat, klorin, dan sulfat) secaratime series. Daririset ini, dapat kami sampaikan bahwa data time series sangat berperan dalamanalisis lingkungan, sehingga layak untuk dikembangkan.

<< English version >> ABSTRACT Many processes can influence river water and groundwater to its current form.Daily variation of water quality data can be analyzed to understand such processes.This research mainly analyzed time series data of TDS from river water to under-stand the processes. We suspect that local drainage has a strong influence to theincreasing values of TDS in the river water. We collected the data from March toNovember 2017 at three locations (from north to south): S. Ciawitali located atCurug Panganten (CP) and at Grand Royal Pancanaka (GRP), and S. Cibeureumlocated at Pondok Hijau Indah (PHI). At each locations we measured air temper-ature, river water temperature, and TDS. The measurements were conducted fourtimes/day, 3 days/week in eight months. To support our claims, we also analyzed310 water quality dataset that were available to classify the samples. We used opensource applications, R, to produce the calculation and the plots. From the threelocations, we find that TDs values on CP and PHI show a cyclic weekly pattern,with the values from PHI are averagely 20% higher than values from CP at givenperiod. We don’t find the same pattern at GRP. The values from that location showa random pattern. Interestingly, we find an increasing trend from June to July. Weargue that the cyclic pattern at CP and PHI are brought by many drainage outletsin the river bank. Such drainage collects domestic waste from housings and nearbyaccommodations (hotels) and tourist objects. Both locations are known as part oftourist object area at northern Bandung. GRP does not show the same situationbecause the TDS most likely only from the nearby GRP housing. The observationsite is located at a man made channel that connect two natural channel through GRPhousing complex. We argue that the TDS values at the channel capture a closedsystem drainage, compare to the open system at CP and PHI. Based on the multi-variable analysis, we also see a close interaction between groundwater and riverwater at various places in Bandung area. This phenomenon should add our under-standing on the patterns of TDS value. Such close interactions between groundwaterand river water, should be the focus of the Bandung authorities. In this such closeinteractions, the contamination present in the river environment could come bothfrom the river and the groundwater system. Both water have the same chance tosend out man-made pollution in the environment.