Air merupakan sumber daya alam yang sangat penting bagi kehidupan. Pertumbuhan penduduk yang pesat dan peningkatan aktivitas menyebabkan meningkamya kebutuhan air dan terjadinya perubahan penggunaan laban dari lahan bervegetasi menjadi Iahan terbangWl. Kedua hal tersebut memberikan dampak yang tidak baik terhadap kelestarian air tanah, terutama di CAT Jakarta. Penelilian ini berfungsi untuk mengetahui . faktor-faktor yang menyebabkan terjadinya penurunan cadangan air tanah di CAT Jakarta, menganalisis pengaruh pertumbuhan penduduk dan peruhahan penggunaan lahan terbadap penurunan cadangan air tanah di CAT Jakarta melalui model sistem dinamis, serta untuk menganalisis skenario yang dapat diterapkan daiam melestarikan air tanah di CAT Jakarta. Penelitian rnenggunakan pendekatan mix method yang menggabungkan metode kuantitatif dan kualitatif dengan menggunakan permodelan sistem dinamis untuk mengatahui hubW1gan antar faktor. Metode penelitian yaitu dengan interpretasi citra satelit dan survey lapangan. Ana1isis yang digunakan untuk menjawab tujuan penelitian menggunakan pennodelan sistem dinamik. Mode) yang dibuat mempunyai validasi yang diukur dengan menggunakan Atvf£ sebesar 3,3!% untuk penduduk dan 0,02% untuk lahan sehingga model dianggap valid. Berdasarkan model faktor-faktor yang mempengaruhi penurunan cadangan air tanah antara lain: menurunnya luas lahan resapan meningkatnya lahan terbangun; meningkatnya jumlah penduduk, rendahnya laju imbuhan air tanah dan rendahnya layanan PAM.

---

Water is a natural resource that is essential for life. Rapid population growth and an increase in the activity causing the increasing need for water and land use change modeling of vegetated area into built up area. Both of these give significant effect for the sustainability of groundwater, especially in Jakarta Groundwater Basin, Aims of this research are try to determine the factors that ted to a decrease in reserves of groundwater in the Jakarta Groundwater Basin (CAT). Analyze the effect of population growth and land use change on groundwater reserves decline in Jakarta"s CAT through dynamic system model, as well as to defined scenarios that can he applied in preserving groundwater in Jakarta's CAT. This research combines both quantitative and qualitative methods. Dynamic system modeling used to determine the relationship between one and another factors while land use change data obtained from satellite imagery and field survey. Dynamic system model validation measured using AME of 3.31% for the population aod 0.02% for the laod so that the model is considered valid. Based on the model, the factors that influence the decline of groundwater reserves include: declining water catclunent area, increasing built up area, increasing population growth, low rate of numerical groundwater and low water service from PAM (Drinking Water Company). Increased of built up area by 0.8% per year as well as the rate of population growth of 2,52% per year causing a decrease in groundwater reserves of 0.49% per year. Preservation of groundwater can be scripted in the model by using a 4 (four) scenarios, which are (1) decrease of built up area (scenario I), (2) decrease in birth rate (scenario II), (3) improved piped water service (scenario III) and (4) combination of decline birth and an increase water service from PAM (scenario IV). The result show that scenario IV is an optimistic scenario that has greatest opportunity to apply and provide better sustainability option for groundwater condition compared to other scenarios.