Daerah Bahaya Banjir Di Sub Daerah Aliran Sungai Sepauk Dan Tempunak, Kabupaten Sintang, Provinsi Kalimantan Barat (Flood Hazard in Sepauk and Tempunak Sub Watersheds, Sintang Regency, West Kalimantan Province)

Flood-prone areas mapping is often constrained by limited data availability at the site level. A quick assessment of sub watershed degradation method can be used to identify the degradation level of a sub watershed includes the flood hazard areas. This method is very easy to be applied at a site level using Geographic Information System (GIS), although it has minimum data. The aim of this study was to analyze the level of flood hazard in Sepauk and Tempunak Sub Watersheds, Sintang Regency, West Kalimantan Province. The required data were DEM/ SRTM (Digital Elevation Model/ Shuttle Radar Topography Mission), daily rainfall, and land cover. Quick assessment of sub watershed degradation method was applied to classify the flood-prone level of the study areas. The results showed that most of the study areas were categorized as high level of flood hazard (78% for Sepauk and 56% for Tempunak). The land covers of those areas were dominated by mixed dryland agriculture, bare land, and settlements. In addition, high level of flood hazard areas in Sepauk Sub Watershed was also affected by the existence of mining and dryland agriculture areas. Since the land cover change is a dynamic process, the flood hazard areas mapping should also be adjusted continuously to minimize the flood impact

Analysis of land cover change and its impact on peak discharge in Jelap Sub-Watershed, Sintang District

ABSTRAK Informasi mengenai debit puncak sangat penting dalam perencanaan pembangunan infrastruktur. Debit puncak dapat diprediksi menggunakan data dari alat pengukur tinggi muka air yang di pasang di outlet Daerah Aliran Sungai (DAS). Namun demikian, tidak semua DAS memiliki alat tersebut, terutama yang berada pada daerah dengan tingkat aksesibilitas rendah. Teknologi penginderaan jauh dapat menggantikan cara tersebut dalam menyediakan data dan informasi sumberdaya alam maupun pemantauan lingkungan. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh perubahan penutupan lahan terhadap debit puncak di Sub DAS Jelap. Sub DAS Jelap merupakan bagian dari DAS Kapuas yang berada di Kabupaten Sintang, Propinsi Kalimantan Barat. Data curah hujan diperoleh dari stasiun pengamatan curah hujan Bandara Susilo. Debit puncak dihitung menggunakan metode Rational dengan memanfaatkan data satelit penginderaan jauh berupa Digital Elevation Model/ Shuttle Radar Topography Mission (DEM/ SRTM). Selama 1990-2016, hutan lahan kering sekunder dan hutan rawa sekunder mengalami penurunan seluas 1298 ha dan 338 ha, sedangkan semak belukar, semak belukar rawa, pertanian lahan kering campur semak, perkebunan dan area pertambangan mengalami peningkatan sebesar 78 ha, 102 ha, 814 ha, 640 ha, dan 2 ha. Perubahan penutupan lahan tersebut telah meningkatkan koefisien runoff dengan rata-rata peningkatan sebesar 0,14%. Dengan luas daerah terbangun kurang dari 1%, debit puncak yang dihasilkan berdasarkan analisis spasial memiliki pola yang hampir sama dengan fluktuasi curah hujan maksimum. Hal ini menunjukkan bahwa dibandingkan faktor lainnya, curah hujan maksimum merupakan faktor yang sangat menentukan nilai debit puncak di Sub DAS Jelap. Kata kunci: Penutupan lahan, curah hujan, debit puncak, Jelap, Sintang English title: Analysis of land cover change and its impact on peak discharge in Jelap Sub-Watershed, Sintang District ABSTRACT Information on peak discharge is crucial in infrastructure development planning. Peak discharge could be predicted using data from water level gauges which installed at the watershed outlet. However, not all of the watersheds have such tools, especially those in areas with low accessibility levels. Remote sensing technology could replace such tools in providing data and information of natural resources as well as environmental monitoring. The objective of this research was to analyze the land cover change and its impact on peak discharge at Jelap Sub-Watershed. Jelap Sub-Watershed is part of Kapuas Watershed located in Sintang District, West Kalimantan Province. The rainfall data were collected from Susilo Airport Rainfall Station. Peak discharge was calculated using a rational method by utilizing remote sensing satellite data in the form of Digital Elevation Model/ Shuttle Radar Topography Mission (DEM/ SRTM). Throughout 1990-2016, the area of secondary dry land forest and secondary swamp forest declined by 1298 ha and 338 ha, while shrubs, swamp shrubs, mixed dry land agriculture, plantations, and mining areas increased by 78 ha, 102 ha, 814 ha, 640 ha, and 2 ha. The change in land cover has increased the runoff coefficient with 0,14% average increment. With built area less than 1%, the peak discharge generated spatially had a similar pattern with the fluctuation of maximum rainfall. Compared to other factors, the maximum rainfall was the most decisive factor to determine peak discharge in Jelap Sub-Watershed. Keywords: Landcover, Rainfall, Peak discharge, Jelap, Sintang Citation: Auliyani, D. (2018). Analisis perubahan penutupan lahan dan pengaruhnya terhadap debit puncak di Sub Daerah Aliran Sungai Jelap, Kabupaten Sintang. Jurnal Ilmu Lingkungan, 16(1),61-67, doi:10.14710/jil.16.1.61-6

Upaya Konservasi Tanah dan Air pada Daerah Pertanian Dataran Tinggi di Sub-Daerah Aliran Sungai Gandul

Land susceptibility to degradation is characterized by the loss of topsoil due to erosion which is considered as a threat to agricultural productivity. Information about land sensitivity to erosion is crucial in determining the appropriate soil and water conservation techniques to avoid land degradation. This study, which was located in the Gandul Sub-Watershed, aims to analyze the level of land sensitivity to erosion in highland agricultural areas. Data analysis was carried out spatially using land system and land-cover maps. Soil and water conservation efforts were determined based on the land function and sensitivity. The land sensitivity to erosion in the Gandul Sub-watershed was categorized into 3 levels which were moderate (3.9%), high (95%), and very high (0.8%). There were various directions for Gandul Sub-Watershed management by considering the level of sensitivity of the land and the function of the area. Creating a ridge is one of the soils and water conservation practices that has been implemented for a long time by local communities as a soil erosion prevention.   Keywords: agriculture, erosion, Gandul, sensitivit

Peak Discharge in Jemelak Subwatershed, Sintang District

Jemelak Sub Watershed is close to the junction of two big rivers, i.e., Kapuas and Melawi. Therefore, this location faces environmental issues such as a flood. To avoid its possible damages, information on peak discharge becomes critical, particularly in calculating the drainage structure. This study was aimed to predict the peak discharge in this area using a rational method. The maximum daily rainfall data from 1998 to 2017 were divided into two periods of 10 years and analyzed. In the first period,  maximum rainfall rangesfrom98.6 to 176.3 mm, while the second period fluctuates from67.6 to 190 mm. Analysis of land cover described that 43.97% of secondary swamp forests turned into shrubs and swamp shrubs in the first period. Furthermore, about 800.71 ha of secondary swamp forest tuned into 582.80 ha of bare land, 181.04 ha of a plantation, and 36.88 ha of swamp shrubs in the second period. About 95.15% of shrubs were also turned into agricultural land mixed with shrubs in the second period. The result showed that the changes in the maximum daily rainfall and land cover simultaneously affected the improvement of the peak discharge by about 2.53% in the first period and 28.30% in the second period. If the peak discharge exceeds the river capacity, then the local flooding will occur along the river border. Keywords: land cover, peak discharge, rainfall, Jemela

Perbandingan Prediksi Hasil Sedimen Menggunakan Pendekatan Model Universal Soil Loss Equation Dengan Pengukuran Langsung (Comparison of Sediment Yield From Prediction Using Universal Soil Loss Equation with Direct Measurement)

Low level of sedimentation is a success indicator of watershed management. Measurement of sedimentation can be conducted directly or through erosion prediction approach. This research aimed to compare sediment yield from prediction by USLE erosion approach using three types formulations of rainfall erosivity with direct measurement. The field data were collected during 2015 in Lowereng Sub Watershed, Sempor District of Kebumen Regency. The slope steepness was derived from ASTER Global Digital Elevation Model and land cover was obtained from World View 2012. Three methods for estimating rainfall erosivity were Utomo and Mahmud, Bols, and Lenvain equations. The USLE applied for every land unit. By considering Sediment Delivery Ratio (SDR), the predicted soil erosion from USLE was converted into sediment yield. The direct measurement of sediment yield was conducted by taking suspended sediment in the outlet of sub watershed. This research indicates that the predicted sediment yield calculated using USLE approach was higher than the direct measurement. The predicted sediment yield using Lenvain's equation was 3.49 ton/ha (196%), which was the closest to the direct measurement (1.18 ton/ha)

Pendugaan Model Pertumbuhan Dan Penyebaran Spasial Populasi Rusa Timor (Cervus Timorensis De Blainville, 1822) Di Taman Nasional Alas Purwo Jawa Timur

Timor deer is ruminant mammals' species with high adaptability which enable them to be introduced easily in to new habitat. The animal was experiencing population decrease which put them in the rare status. The research was aimed at the estimation of demographic parameter, population growth model, and the determination of spatial distribution pattern of the timor deer population in Alas Purwo National Park (APNP). Animal inventory was conducted using strip transect method with sample unit of 1.5 km length and 100 m width strips. Analyses were conducted on demography parameter (size and density, sex ratio, birth rate/natality and mortality), spatial distribution pattern, and population growth model estimation. The result showed that timor deer in APNP has population size of 8157 ± 1224 individuals with population density of 0,20 ± 0,03 individuals/ha. Population size in general was 1 – 8 individuals/group. The age structure of the population was progressive population with reproductive sex ratio of 1 : 2.3. Rough birth rate/natality was 0.19, while juvenile and fawn mortality was 0.13 and 0.31. The population was spatially distributed in group. Growth model of Timor deer was logistic model, with population growth rate of 0.22 in 38,844 individuals/year habitat carrying capacity

PENDUGAAN MODEL PERTUMBUHAN DAN PENYEBARAN SPASIAL POPULASI RUSA TIMOR (Cervus timorensis de Blainville, 1822) DI TAMAN NASIONAL ALAS PURWO JAWA TIMUR

Timor deer is ruminant mammals’ species with high adaptability which enable them to be introduced easily in to new habitat. The animal was experiencing population decrease which put them in the rare status. The research was aimed at the estimation of demographic parameter, population growth model, and the determination of spatial distribution pattern of the timor deer population in Alas Purwo National Park (APNP). Animal inventory was conducted using strip transect method with sample unit of 1.5 km length and 100 m width strips. Analyses were conducted on demography parameter (size and density, sex ratio, birth rate/natality and mortality), spatial distribution pattern, and population growth model estimation. The result showed that timor deer in APNP has population size of 8157 ± 1224 individuals with population density of 0,20 ± 0,03 individuals/ha. Population size in general was 1 – 8 individuals/group. The age structure of the population was progressive population with reproductive sex ratio of 1 : 2.3. Rough birth rate/natality was 0.19, while juvenile and fawn mortality was 0.13 and 0.31. The population was spatially distributed in group. Growth model of Timor deer was logistic model, with population growth rate of 0.22 in 38,844 individuals/year habitat carrying capacity.Keywords: Cervus timorensis, demographic, spatial distribution, growth

Pola Hujan Kabupaten Blora, Propinsi Jawa Tengah (Studi Kasus : Sub DAS Cemoro dan Modang)

Sebagai bagian dari siklus hidrologi, curah hujan sangat penting untuk dipelajari karena sifatnya yang sangat variatif baik secara temporal maupun spasial. Pola curah hujan dapat digunakan sebagai dasar identifikasi perubahan iklim. Dalam lingkup pengelolaan Daerah Aliran Sungai (DAS), variasi hujan akan mempengaruhi respon hidrologi suatu DAS. Tujuan dari penelitian ini adalah untuk mengetahui karakteristik hujan di Sub DAS Cemoro dan Modang, Kabupaten Blora Propinsi Jawa Tengah. Kedua wilayah tersebut merupakan Sub DAS dengan penutupan hutan jati. Data yang digunakan dalam penelitian ini adalah data hujan dari beberapa stasiun pengamatan curah hujan tahun 2001-2017, yang selanjutnya dianalisis secara deskriptif kualitatif. Dalam kurun waktu 17 tahun pengamatan, diketahui bahwa curah hujan tahunan antara Sub DAS Cemoro dan Modang hampir sama. Curah hujan bulanan menunjukkan peningkatan sejak Bulan September dan mulai menurun pada Bulan April. Bulan kering berlangsung selama 6 bulan, sedangkan bulan basah terjadi selama 4 bulan. Berdasarkan klasifikasi Oldeman, lokasi penelitian berada dalam zona iklim D3. Tren curah hujan tahunan di kedua Sub DAS mengalami penurunan sejak 2001 dan sedikit terjadi kenaikan pada 2013 hingga 2017. Untuk menjaga keseimbangan tata air, keberadaan hutan di lokasi penelitian perlu dipertahankan untuk mendukung kehidupan masyarakat di kawasan hilirnya

Temporal Distribution of Sediment Yield From Catchments Covered by Different Pine Plantation Areas

Soil erosion and sedimentation are environmental problems faced by tropical countries. Many researches on soil erosion-sedimentation have been conducted with various results. Quantifying soil erosion-sedimentation and its temporal distribution are important for watershed management. Therefore, a study with the objective to quantify the amount of suspended sediment from catchments under various pine plantation areas was conducted. The research was undertaken during 2010 to 2017 in seven catchments with various percentage of pine coverage in Kebumen Regency, Central Java Province. The rainfall data were collected from two rainfall stations. A tide gauge was installed at the outlet of each catchment to monitor stream water level. The water samples for every stream water level increment were analyzed to obtain sediment concentration. The results showed that monthly suspended sediment of the catchments was high in January to April and October to December, and low in May to September. The annual suspended sediment fluctuated during the study period. Non-linear correlations were observed between suspended sediment and rainfall as well as suspended sediment and percentage pine areas. The line trend between suspended sediment and percentage of pine areas showed that the increase in pine areas decreased suspended sediment, with the slope of the graph is sharp at the percentage of pine areas from 8% to 40%, then is gentle for pine plantation areas more than 40%

Partisipasi Masyarakat dalam Rehabilitasi Mangrove di Desa Pesisir Kabupaten Rembang : Tinjauan Berdasarkan Tahap Perencanaan, Pelaksanaan, dan Pemeliharaan

ABSTRAK DIAH AULIYANI. Partisipasi Masyarakat Dalam Rehabilitasi Mangrove di Desa Pesisir Kabupaten Rembang : Tinjauan Berdasarkan Tahap Perencanaan, Pelaksanaan, dan Pemeliharaan. Dibimbing oleh Drs. Ign. BOEDI HENDRARTO, M.Sc., Ph.D dan Dr. Dra. KISMARTINI, M.Si Rehabilitasi mangrove di Kabupaten Rembang telah menunjukkan hasil yang cukup signifikan dengan adanya peran serta yang baik dari masyarakat. Namun demikian, diduga tidak semua masyarakat pesisir memiliki tingkat partisipasi yang sama terhadap upaya rehabilitasi yang dilakukan. Tujuan dari penelitian ini adalah untuk menganalisis tingkat partisipasi masyarakat beserta faktor-faktor yang mempengaruhinya dalam rehabilitasi mangrove di desa pesisir Kabupaten Rembang. Lokasi penelitian dipilih secara purposive. Responden ditetapkan sebanyak 93 orang, terdiri atas : 17 orang dari Desa Tunggulsari, 41 orang dari Desa Pasarbanggi, 19 orang dari Dusun Kaliuntu, dan 16 orang dari Desa Dasun. Pengumpulan data dilakukan dengan observasi, wawancara, kuisioner, dan studi pustaka. Variabel yang diamati terdiri atas : (1) variabel bebas, meliputi : umur, lama mukim, tingkat pendidikan, jumlah anggota keluarga, persepsi, jarak rumah terhadap mangrove, peran pemerintah, dan aktivitas kelompok; serta (2) variabel terikat, yaitu partisipasi masyarakat meliputi tahap perencanaan, pelaksanaan, dan pemeliharaan. Tingkat partisipasi diperoleh dengan menggunakan teknik skoring, dan faktor-faktor yang mempengaruhinya dianalisis dengan menggunakan principal component analysis (PCA). Dari penelitian ini diketahui bahwa tingkat partisipasi pada tahap perencanaan, pelaksanaan, dan pemeliharaan menunjukkan pola yang semakin menurun. Tingkat partisipasi masyarakat Kaliuntu berada pada kategori sedang sampai tinggi, sedangkan tingkat partisipasi masyarakat Tunggulsari, Pasarbanggi, dan Dasun berada pada kategori rendah sampai sedang. Faktor dominan yang berpengaruh pada tingkat partisipasi tersebut adalah faktor persepsi, peran pemerintah, dan aktivitas kelompok dengan nilai korelasi masing-masing faktor terhadap partisipasi masyarakat sebesar 0,725; 0,581; dan 0,524. Kata Kunci : partisipasi masyarakat, rehabilitasi mangrove, Kabupaten Remban