Evaluation of Carrying Capacity and Conservation Scenarios of Wosi Watershed at Manokwari Regency, West Papua

Abstract

Around 12.62% of watersheds in Indonesia are damaged and need restoration immediately to prevent floods, landslides, and other related disasters. This study aimed to evaluate the Wosi watershed and formulate conservation scenarios to improve its conditions. The data collection included hydrology (quantity, continuity, and water quality), land (critical land index, percentage of vegetation cover, and erosion index), socio-economic (population pressure, welfare level, existence, and regulations enforcement), building investment (city classification and water building value classification), and the use of space (protected areas and cultivation areas). The evaluation of carrying capacity used a scoring analysis. The scenarios formulation used the information on potential carrying capacity and conservation strategies. The results suggested that the carrying capacity of the Wosi watershed from 2016-2019 had fallen into "bad" and "very bad" categories. To improve these conditions, the government can assign the riparian areas as a government asset, build ponds and dikes in the flood-prone areas, apply small recharge pond (SRP) on the cacao plantations, and assign Wosi Rendani protected forest (HLWR) as an urban forest. The implementation of these conservation strategies will result in the improvement of (a) the carrying capacity of the Wosi watershed and (b) the status into the "good" category to support environmentally friendly development in Manokwari city.

Biophysical characteristics of Wosi Watershed area in Manokwari Regency, Indonesia

“…Impact of Watershed Characteristics on Hydrology Mahmud et al (2021a) found out that the carrying capacity of the Wosi Watershed is categorized as bad and is one of the watersheds in Manokwari Regency that must be restored. Water discharge is a very important part of hydrological parameters to evaluate the extent to which rainfall affects surface runoff, river water level, and river capacity.…”

“…This shows that there is a decrease in the carrying capacity of the watershed to receive, absorb, and drain rainwater into the river. According to Mahmud et al (2021a), if the FRC is low, the water flows throughout the year without showing a significant water level. The flow of water is not only in the rainy season but continues to flow even during the dry season.…”

“…Pamuji and Hardianti (2019) argued that the Wosi River could not accommodate the peak flow during high-intensity of rainfall, thus causing flooding. The Wosi area is located in the capital city of West Papua Province, which will continue to grow and develop, but its carrying capacity is decreasing (Mahmud et al 2021a). The Wosi watershed has become a source of catastrophic flooding for several regions in Manokwari, particularly those living downstream of the watershed, such as the area of Wosi market, the green valley, around the Rendani Airport, the Bugis Village, and the Javanese Village.…”

Dampak Perusakan Antropogenik Terhadap Sedimentasi dan Erosi Pada Hutan Lindung Wosi Rendani Di Kabupaten Manokwari

“…Perusakan hutan merupakan masalah yang tidak bisa dibiarkan, sebagai solusi diperlukan pemahaman yang menyeluruh tentang faktor-faktor biofisik, ekonomi dan sosial (Purnomo dan Mendoza, 2011). Sebagaimana degradasi dan deforestasi hutan lindung Remu oleh pengambilan galian C berdampak banjir kota Sorong (Kompas, 2020), kerusakan dan penurunan luas hutan lindung di Bogor berdampak longsor tahun 2020 (Sidiq, 2020), penyusutan Hutan Lindung Wosi Rendani (HLWR) menjadi 88.2 ha dari semula 300.6 ha yang berdampak banjir lebih dari satu kali dalam setahun (Mahmud et al, 2021).…”

“…Padahal kawasan semua itu masuk HLWR bagian dari DAS Wosi, sehingga tidak heran saat ini hutan hanya tersisa 26%. Menurut Mahmud et al (2021) daya dukung DAS Wosi berkategori buruk dan sangat buruk yang dikategorikan sebagai DAS yang harus dipulihkan. Begitu juga DAS Wosi merupakan salah satu dari tujuh DAS yang harus dipulihkan berada dalam ibu kota Provinsi Papua Barat (BPDASHL Remu Ransiki, 2016).…”