IDENTIFIKASI LAJU EROSI DAN LAJU SEDIMENTASI PADA WADUK WONOSARI KABUPATEN BENGKALIS

Generally, people who live in island areas depend on the management of water resources, such as the distribution of raw water from reservoirs. Bengkalis Regency is an island area and has a Wonosari reservoir which functions as a source of raw water for the people. Often, there is drought or lack of water supply to the people during the summer. One of the factors indicating the cause is the reduced volume of water storage in the reservoir due to sedimentation which can be calculated using the equations of erosion rate and sedimentation rate. The method used is the explorative-survey which obtains supporting data from direct field surveys and spatial, environmental and territorial approaches. The results for this study proved that sedimentation in the reservoir did not significantly affect the occurrence of water shortages which caused water needs to be not fulfilled in the community. The rates of erosion and sedimentation rates are 5.415 ton/ha/yr and 0.164 ton/ha/yr (very light erosion hazard category)

Pendekatan Model Wasp Pada Pengendalian Pencemaran Sungai Dengan Parameter Uji Cod

The rapid development requires enormous natural resources. So it appears that in development there is an overuse of natural resources, which results in disruption of the water system balance. Various impacts will occur as a result of unbalanced use of natural resources, the use of unbalanced natural resources around the Siak river area, causing an increase in pollution entering the river. Regulation of the Minister of PUPR Number 4 of 2015 concerning Criteria and Designation of River Areas, Siak River is one of the major rivers that receive national attention and is also included in the national strategic river category. Control of river pollution is done by analyzing the WASP modeling and the existing condition of the Siak river, the effect of the levels on the parameters of the mainstay discharge and the mainstay discharge and the percentage of pollution load reduction carried out to meet the class II quality standards. The results showed that theoverall condition of the Siak river was polluted. The average excess capacity of the COD pollution load at the time of the depandable discharge is -454,516 kg/day. Then at the time of the depandable discharge isvalued at -181,087 kg/day. The control effort taken is to reduce the COD contamination load so that the capacity of the pollution load is +177,742 kg/day when the depandable discharge is maximum and +72,536kg/day when the depandable discharge is minimum. Percentage reduction of COD contamination load at the minimum and maximum depandable discharge to meet the class II quality standard of 50%

Penentuan Muka Air dan Jenis Lapisan Tanah Menggunakan Metode Geolistrik

The tools that are often used, such as sondir and SPT, are quite heavy and require a long measurement time span, making it difficult to determine the shear strength of the soil, both in the laboratory and in the field.. This study uses the resistivity geoelectric method of the Wenner Alpha configuration supported by the Naniura NRD 300 HF tool. The aim is to determine the estimated groundwater level and determine the resistivity value of each type of soil layer below the surface of the study area. This study performs 2D measurements to calculate 1-D and 2-D geoelectric resistivity with electrodes arranged lengthwise to form a straight line. Using the IP2WIN software, the measurement results are processed to produce a 2D apparent resistivity section that describes the color image distribution values of the soil surface layer. The measurement results on track 1 shows a resistivity value between 3,512 – 1.539 Ω.m with a length of 90 m at a depth to 15.05 m. The predicted groundwater level elevation is located 0.656 meters below the surface of the ground. Track 2 has a span length of 60 meters and resistivity values ranging from 29.55 to 207.1.m, with a predicted groundwater level at a depth of 0.72 m below the surface. The types of soil layers are clay mixed with sand, sand mixed with gravel and sandstone mixed with gravel.Alat-alat yang sering digunakan seperti SPT dan sondir cukup berat dan memerlukan rentang waktu pengukuran yang lama sehingga sulit untuk menentukan kuat geser tanah baik di laboratorium maupun di lapangan. Studi ini menggunakan metode geolistrik resistivitas konfigurasi Wenner Alpha didukung alat Naniura NRD 300 HF. Tujuannya untuk mengetahui perkiraan tinggi muka air tanah dan menentukan nilai resistivitas masing-masing jenis lapisan tanah di bawah permukaan daerah studi. Studi ini melakukan pengukuran 2D untuk menghitung tahanan jenis geolistrik 1-D dan 2-D dengan elektroda di susun memanjang membentuk garis lurus. Hasil pengukuran diolah menggunakan software IP2WIN untuk mendapatkan penampang resistivitas semu 2D yang menggambarkan nilai sebaran lapisan yang permukaan tanahnya ditunjukkan pada citra berwarna. Hasil pengukuran pada lintasan 1 menunjukkan nilai resistivitas antara 3,512 – 1.539 Ω.m dengan Panjang bentang 90 m pada kedalaman sampai 15,05 m. Ketinggian muka air tanah diprediksi terletak 0,656 m di bawah permukaan tanah. Lintasan 2 memiliki panjang bentang 60 m dan nilai resistivitas berkisar antara 29,55 hingga 207,1 m, dengan prediksi muka air tanah pada kedalaman 0,72 m di bawah permukaan. Jenis lapisan tanah berupa lempung bercampur pasir, pasir bercampur kerikil dan batu pasir bercampur kerikil