Wahyu Wisnu Wijaya, Wahyu Wisnu
Balai Penelitian Teknologi Kehutanan Pengelolaan Daerah Aliran Sungai

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Specific Peak Discharge of Two Catchments Covered by Teak Forest with Different Area Percentages Basuki, Tyas Mutiara; Adi, Rahardyan Nugroho; Wijaya, Wahyu Wisnu
Forum Geografi Vol 31, No 1 (2017): July 2017
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v31i1.3236

Abstract

In watershed area, forest has important roles in relation with peak discharge. This  research was conducted to study the impacts of teak forest on peak discharge. On-screen digitizing of IKONOS imagery was done to classify the land cover of the study area. Kejalen and Gagakan catchments covered by old teak forests by 74% and 53% respectively, were chosen as the study area. These catchments are located in Blora Regency. Automatic streamflow recorder was set at the outlet of each catchment and subsequently, peak discharges were examined from the recorded data. During the observation, there were 36 evidences of specific peak discharge. The results showed that a trend of lower peak discharges occurred in Kejalen catchment which has the higher percentage of teak forest area  in compared to Gagakan catchment with lower percentage of teak forest area, except when extreme rainfalls happened. At rainfall of 163 mm/day, specific peak discharge in Kejalen was higher than in Gagakan catchment. Although there is a relationship between specific peak discharge and the percentage of forest cover area, the increase of specific peak discharge is not only affected by forest cover, but also affected by daily rainfall, antecedent soil moisture, and rainfall intensity. Coefficients of determination between specific peak discharge and daily rainfall are 0.64 and 0.61 for Kejalen and Gagakan catchments, respectively.
Temporal distribution of sediment yield from catchments covered by different pine plantation areas Basuki, Tyas Mutiara; Pramono, Irfan Budi; Adi, Rahardyan Nugroho; Nugrahanto, Esa Bagus; Auliyani, Diah; Wijaya, Wahyu Wisnu
Journal of Degraded and Mining Lands Management Vol 5, No 3 (2018)
Publisher : University of Brawjiaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1047.532 KB) | DOI: 10.15243/jdmlm.2018.053.1259

Abstract

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%.
IDENTIFIKASI SEKTOR EKONOMI UNGGULAN DAN KETIMPANGAN PENDAPATAN ANTAR KABUPATEN DI SUB DAS BENGAWAN SOLO HULU Cahyono, S Andy; Wijaya, Wahyu Wisnu
Jurnal Penelitian Sosial dan Ekonomi Kehutanan Vol 11, No 1 (2014): Jurnal Penelitian Sosial dan Ekonomi Kehutanan
Publisher : Pusat Penelitian dan Pengembangan Sosial, Ekonomi, Kebijakan dan Perubahan Iklim

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/jpsek.2014.11.1.32-43

Abstract

Tujuan penelitian ini adalah untuk (1) mengidentifikasi sektor ekonomi unggulan dan (2) menganalisis ketimpangan pendapatan antar kabupaten di Sub DAS Bengawan Solo Hulu. Penelitian dilakukan di 5 kabupaten: Wonogiri, Boyolali, Klaten, Sragen, dan Karanganyar. Analisis data menggunakan tipologi Klassen untuk mengetahui pola dan struktur ekonomi, Location Quotient (LQ) untuk mengidentifikasi sektor unggulan, Indeks Williamson untuk mengetahui disparitas ekonomi, dan kontribusi sektoral untuk mengetahui peran sektoral. Hasil penelitian menunjukkan bahwa sektor unggulan berbeda tiap kabupaten, yaitu Wonogiri (pengangkutan dan komunikasi), Karanganyar (industri pengolahan), Boyolali (keuangan, real estat, dan jasa perusahaan), Sragen (pertanian, peternakan, kehutanan, dan perikanan), dan Klaten (konstruksi). Sektor ekonomi unggulan di setiap kabupaten bervariasi tergantung ketersediaan sumberdaya dan keunggulan komparatif. Berdasarkan pola dan struktur ekonominya, Kabupaten Karanganyar termasuk daerah maju dan berkembang pesat tetapi Wonogiri termasuk daerah terbelakang. Hasil penelitian juga menunjukkan disparitas pendapatan antar daerah di masing- masing kabupaten terkategori rendah (0,25) dan cenderung meningkat. Kebijakan pembangunan ekonomi dengan pertumbuhan ekonomi tinggi dan disparitas rendah dapat dilakukan dengan pengembangan sektor unggulan secara inklusif dan memperhatikan transformasi ekonomi yang terjadi di tiap kabupaten.
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) Auliyani, Diah; Wijaya, Wahyu Wisnu
Jurnal Penelitian Pengelolaan Daerah Aliran Sungai Vol 1, No 1 (2017): Jurnal Penelitian Pengelolaan Daerah Aliran Sungai
Publisher : Balai Penelitian dan Pengembangan Teknologi Pengelolaan DAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/jppdas.2017.1.1.61-71

Abstract

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).
Baseflow and lowflow of catchments covered by various old teak forest areas Basuki, Tyas Mutiara; Nugrahanto, Esa Bagus; Pramono, Irfan Budi; Wijaya, Wahyu Wisnu
Journal of Degraded and Mining Lands Management Vol 6, No 2 (2019)
Publisher : Brawijaya University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1019.082 KB) | DOI: 10.15243/jdmlm.2019.062.1609

Abstract

Drought has become a severe disaster faced by several regions in Java, Indonesia due to land cover changes including forest conversion and the increase in air temperature. In this regards, the availability of forests related to lowflow has been a controversial debate. Forest in Java is dominated by teak; however, the hydrological teak forest has not been well known. Therefore, a research has been undertaken to know the baseflow and low-flow of teak catchments covered by various old teak forest areas. The research areas were in Blora District, Central Java, Indonesia. Data of2008-2015 from five catchments with areas of 3.38, 13.47, 20.14, 27.79, 64.80, and 69.20 ha and covered by old teak forests of 82, 82, 74, 70, and 53% of the catchment were analyzed. In this study, baseflow is the delayed flow from bank storage, and low-flow is stream flow in the dry season. The results showed that baseflow is affected by the percentage of old teak plantation areas, rainfall and antecedent soil moisture condition. Areas of the old teak plantation and the baseflow show negative and non-linear correlation. High low-flow occurs in the catchments with the percentage of old teak plantation about 74 to 70%.
Spatial Analysis of Land Degradation Susceptibility and Alternative Plants for Its Rehabilitation Auliyani, Diah; Basuki, Tyas Mutiara; Wijaya, Wahyu Wisnu
Forum Geografi Vol 33, No 1 (2019): July 2019
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v33i1.7499

Abstract

One of the drawbacks of developing plants for the rehabilitation of degraded land in Indonesia is the relative lack of information about species that are suited to the local conditions. Therefore, spatial information on land degradation and the plants suitable for rehabilitation is crucial. The objectives of this study were to map the susceptibility of land to degradation and to identify some alternative species for its rehabilitation. The research was conducted in Jang Watershed, Bintan Island, Kepulauan Riau Province, Indonesia. A quick assessment of land degradation was carried out to classify the degree of land susceptibility. The land suitability evaluation was conducted manually by matching the existing biophysical condition and plant growth requirements using a geographic information system. This analysis was applied for annual plants, such as Acacia mangium, Durio zibethinus, Artocarpus champeden, Theobroma cacao and Hevea brassiliensis. Furthermore, the maps of land susceptibility to degradation and species suitability were overlaid and the result was used to provide recommendations for rehabilitating the degraded land. This study showed that 22% of the Jang Watershed area can be categorised as highly susceptible to degradation. The suitability analysis illustrated that 59% of the degraded areas were suitable for Acacia mangium. The planting of fast-growing species such as Acacia mangium is expected to improve the physical, chemical and biological properties of the soil.