DEVELOPMENT OF WATER CATCHMENT AREAS BY EXTENTIFICATION OF URBAN GREEN SPACES AND ABSORPTION WELLS TO FULFILL THE WATER NEEDS IN CIMAHI

• Main Author: Fikri Fadhilah, Muhamad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64254
• Institution: Institut Teknologi Bandung

Cimahi is one of the cities in Indonesia with high and dense population, even the population growth in this city can reach 2% annually. The density and population growth in this city has been threatened the existence of vegetation cover. As we know, vegetation area has many ecological benefits to support human life, one of them is maintaining the hydrological function (water resources). The threat to vegetation area caused by the high population can be known by the number of Urban Green Spaces (RTH) in Cimahi which does not meet the recent rules or standard, where only 9.34% of the total area of Cimahi is Urban Green Spaces. It certainly impacts the condition of the water catchment area where there are 3.64 Km² of the water catchment area that is already in the critical category. The condition of Urban Green Spaces are aggravated by the increasing exploitation of groundwater which is caused by the high population growth. As a result of these problems, Cimahi experienced a significant decrement in groundwater level of up to 20 cm/year, resulting in several sub-districts such as Melong, Leuwigajah, and Cibeureum experiencing water shortages. With all these conditions, it can be predicted that Cimahi will experience a water deficit starting in 2030. To prevent this disaster, it is necessary to take actions related to the management of environmental issues by developing the catchment areas in terms of quantity and quality. The objectives of this research include (1) predicting the supply and demand of water in Cimahi with dynamic modeling, (2) determining the allocation of urban green space development & absorption well in potential areas, (3) and determining directions or solutions to fulfill the water needs by increasing the function of water catchment area through the development of urban green space and absorption wells. These are methods used in compiling this research, which include; predictions of water demand and supply are carried out for the next 10 years in 3 Districts of Cimahi separately with several variables including biophysical conditions (land cover, rainfall/climate, soil type, land slope), socio-economic conditions (population, population growth, number of industrial units, economic growth) and conditions of water resource potential (river discharge, groundwater potential, PAM/PDAM supply capacity). Meanwhile, the determination about allocation of urban green space is carried out by analyzing the condition of the water catchment area by overlapping/overlaying maps of rainfall, soil type, land slope, and land cover. The location of land that is in critical condition and public lands are designated as urban green space development areas. Meanwhile, to determine the location of the potential absorption wells, it is carried out based on the applicable technical guidelines/guidance for the construction of the absorption wells. In determining the direction or solution for improving the function of the water catchment area carried out by considering the results of predictions of water demand/supply, the number of shortages of urban green space, the allocation of urban green space, and potential absorption wells, to interview results and spatial policy documents such as the Regional Spatial Plan (RTRW). The results of the prediction of water demand and supply indicate that Cimahi City will experience a water crisis starting from 2029 with a total water deficit of 8.22 million M³. The prediction results also show that South Cimahi is the area that experience the most crisis of water availability which the water crisis has occurred since 2022 and peaked in 2029 with a water sufficiency of only 59.83%. The amount of water shortage shows that the City of Cimahi needs to add urban green space as a water catchment area of 355 hectares to cover water shortages in the future. Meanwhile, the results of the analysis of the allocation of potential urban green spaces show that there are only 142.83 hectares spread across North and South Cimahi that available to build for urban green space. With the lack of potential land available for development, it is necessary to add some absorption wells in potential areas which include Melong, Utama, Cibeureum, and increase the supply capacity of PDAM/PAM. So with the results obtained, it can be formulated the directions/solution for the development of water catchment areas to fulfill the water needs including (1) the current area of urban green space needs to be maintained entirely, (2) adding 142.8 Ha of urban green space in North and South Cimahi, (3) building 1.576 units of absorption wells in 3 Sub-district in South Cimahi and (4) increasing 100 l/s of supply capacity of PDAM/PAM.