Papers by Denik Sri Krisnayanti
International journal of safety and security engineering, Apr 26, 2024
Landslide disasters in Indonesia often cause significant damage to public facilities, agricultura... more Landslide disasters in Indonesia often cause significant damage to public facilities, agricultural lands, and result in human casualties. This study was conducted to deeply understand the dynamics and causes of landslides and to develop effective disaster mitigation strategies in areas vulnerable to soil movement. The focus of the research is on the rotational landslide incident that occurred on the Trans Timor National Road KM 73, Noelmina Village, Takari District, Kupang Regency, East Nusa Tenggara Province, on February 17, 2023. Through a methodological approach that includes geomorphological analysis, evaluation of hydrological conditions, and land use study, this research identifies the main factors causing the landslide, including the changeable nature of Bobonaro clay soil, increased soil saturation due to hydrological conditions, and increased water load in the basin area due to land use. The findings emphasize the importance of efficient hydrological management, careful land use planning, and strengthening the capacity of local communities in landslide disaster mitigation. Recommendations for disaster mitigation include the development of infrastructure that is resistant to soil movement, vegetation planting for slope stabilization, and community education on sustainable land use practices. This research provides a significant contribution to disaster mitigation efforts in Indonesia by highlighting an approach based on a comprehensive understanding of the causes of landslides and effective adaptation strategies.
JURNAL SUMBER DAYA AIR
Kupang City and Kupang Regency have semiarid climatological conditions where annual rainfall rang... more Kupang City and Kupang Regency have semiarid climatological conditions where annual rainfall ranges from an average of 1,250 mm/year. Kupang City and Kupang Regency experience long days without rain, which potentially causes meteorological drought. The study aims to determine the value and distribution of the drought index in Kupang City and Kupang Regency. This study uses the Standardized Precipitation Index (SPI) method using rainfall data for 21 years (1998-2018) from 12 rainfall stations, while the mapping uses ArcGIS Software. The results obtained from this study are the extreme level of drought in Kupang Regency and Kupang City occurred in 2015-2016. A 1-month SPI Kupang City experienced the highest drought in January 2004 at -3.48, while Kupang Regency occurred in November 2015 at -3.06. The 3-month SPI Kupang City experienced the highest drought in January 2016 at -3.85, while Kupang Regency occurred in December 2012 at -4.13. The 6-month SPI of Kupang City experienced the...
Media Komunikasi Teknik Sipil, Jul 29, 2022
A watershed in which the observed discharge data is not available or incomplete becomes a problem... more A watershed in which the observed discharge data is not available or incomplete becomes a problem in the water utilization projects. Observation discharge data obtained from Pos Duga Air Sungai Temef is less reliable because the measurement of water level data for the last few years has been carried out by direct observation without using a discharge measuring device. Obtain river discharge data, it can be done by simulating rainfall data into discharge data, one of them is NRECA Model. In NRECA Model, there are several parameters, namely index soil moisture capacity (nominal), Percent Sub Surface (PSUB), Ground Water Flow (GWF), and crop coefficient (kc). Determination of the parameters NRECA Model was obtained by trial and error based on the value limit so that the coefficient correlation (r) between observation discharge and simulation discharge was close to 1. The values used for the index soil moisture capacity (nominal), percent sub surface (PSUB), ground water flow (GWF), and crop coefficient (kc) are 0,20; 0,85; 0,50; and 0,60.
Civil and Environmental Science
Flores Island is one of four big islands in NTT province with an area ±13,540 km 2 divided into 8... more Flores Island is one of four big islands in NTT province with an area ±13,540 km 2 divided into 8 districts. The area is included in areas with unequal distribution of rainfall. Therefore, the amount of water availability during the dry season is relatively low then require to attempts of rainwater harvesting. One of the alternatives is by building a retention pond. The important parameter in the calculation of water availability is the value of runoff coefficient. The purpose of this research is to invent the runoff coefficient value of 30 retention ponds in 8 districts of Flores Island. In this study use rainfall data, climatology and technical of retention basin for the analysis of run off coefficient. The analysis method uses the Penman modification for evapotranspiration calculation and method F.J. Mock for discharge calculation. The result in graphical model uses monthly rainfall data and land slope data. Based on the analytical calculation method, the value of run off coefficient for each district in Flores was ranging 0.00 -0.72. The minimum value of runoff coefficient happened in November was ranging from 0.00 -0.39, and the maximum value of runoff coefficient happened in January was ranging from 0.48 -0.72.
Journal of Southwest Jiaotong University
This research intends to build the simulation of the Raknamo reservoir operation as to adaptation... more This research intends to build the simulation of the Raknamo reservoir operation as to adaptation to the climate change impact in the semi-arid area. The methodology consists of the simulation for building the reservoir operation to produce the optimal result. The optimization and simulation were carried out in the Raknamo dam that is located in the Raknamo village-Amabi Oefeto district-Kupang regency-NTT province. The development of the Raknamo dam is intended to fulfill the demands of irrigation water, raw water, and mini-hydro electrical generation. The water service is prioritized for irrigation that needs the water about 1.05 m3/s (1,050 l/s) through the water intake channel, which is flowed to rotate the turbine that will produce the electricity about 0.21 MW. The total of water that is needed including the raw water is 0.1 m3/s (100 l/s). The analysis results show that the water availability is unbalanced with the large outflow demand. This means that there is happened the wa...
Journal of Hunan University Natural Sciences
The Noel Puames River is the main river in the Raknamo reservoir used for various purposes, such ... more The Noel Puames River is the main river in the Raknamo reservoir used for various purposes, such as irrigation water needs, raw water, fisheries, and others. In the rainy season, the Noel Puames River has enough large discharges, while, in the dry season, the Noel Puames River has almost no base flow. This study aims to determine the effect of climate change on rainfall characteristics in the Raknamo watershed. The methods used include the collection of rainfall data and watershed maps. The rainfall data were used by the Raknamo and Camplong rainfall stations for 25 years of observation resulting in the characteristics of rainfall decrease from time to time, especially the maximum daily rainfall. Annual rainfall tends to increase at Camplong station, but not at Raknamo station, which has the closest location to the Raknamo watershed. There has been a climate change in the Raknamo watershed as indicated by the Z value, which is not equal to zero (Z ≠ 0) although not significant excep...
Jurnal Teknik Pengairan: Journal of Water Resources, Dec 1, 2021
Desa Bolok merupakan salah satu desa di Kabupaten Kupang yang belum terlayani oleh pelayanan peny... more Desa Bolok merupakan salah satu desa di Kabupaten Kupang yang belum terlayani oleh pelayanan penyediaan air bersih. Belum tersedianya pelayanan air bersih menjadi masalah untuk masyarakat memenuhi kebutuhan air hariannya. Penelitian ini ditujukan untuk merencanakan jaringan perpipaan air bersih agar membantu masyarakat Desa Bolok memenuhi kebutuhan air bersihnya. Jaringan perpipaan air bersih direncanakan menggunakan software Epanet 2.0 dengan perhitungan kehilangan energi menggunakan metode Hazen William. Terdapat 2 sumber air yang bisa dipakai yaitu sumur bor Taman Eden milik Desa Bolok dengan debit air 1,314 ltr/detik dan sumur bor milik PDAM Kabupaten Kupang dengan debit air 5 ltr/detik. Proyeksi penduduk pada tahun 2028 dilakukan dengan metode aritmatik, geometrik dan least square. Berdasarkan hasil uji standar deviasi dan koefisien korelasi, maka digunakan hasil proyeksi penduduk dengan metode geometrik yaitu 4075 jiwa. Hasil proyeksi penduduk ini kemudian digunakan untuk proyeksi terhadap fasilitas umum yang ada di Desa Bolok. Berdasarkan perhitungan, total kebutuhan rata-rata air Desa Bolok pada tahun 2028 adalah 5,00 ltr/detik. Pipa yang digunakan adalah galvanized iron pipe (GIP) dengan diameter berkisar antara 25 mm -125 mm. Volume reservoir yang direncanakan adalah 90 m 3 dengan ukuran panjang = 5 m, lebar = 4,5 m dan tinggi = 4 m.
Pelimpah bertangga merupakan modifikasi dari profil standar untuk pelimpah tipe ogee. Tangga pada... more Pelimpah bertangga merupakan modifikasi dari profil standar untuk pelimpah tipe ogee. Tangga pada saluran pelimpah meningkatkan peredaman energi yang lebih tinggi karena energi aliran sudah terdistribusi pada anak-anak tangga dan dengan demikian mengurangi besarnya kebutuhan geometri kolam olak di kaki pelimpah. Dalam aliran tenggelam, tangga bertindak sebagai faktor kekasaran yang besar karena sebagian besar energi hilang untuk mempertahankan pusaran horisontal di bawah lapis batas semu. Penelitian ini bertujuan untuk menyelidiki pengaruh titik pemasukan udara (Li/ks) terhadap nilai kehilangan energi relatif (∆E1/E0) pada pelimpah bertangga dalam regim aliran tenggelam. Pada penelitian ini dilakukan pengujian 12 model pelimpah bertangga dengan perlakuan rasio (yc/h). Sudut kemiringan pelimpah (θ) yang digunakan 30˚ dan 45˚, jumlah anak tangga (N) 40, 20 dan 10, serta permukaan tangga tipe datar dan menggunakan ambang. Kedalaman kritis terhadap tinggi tangga (yc/h) berkisar 0.70 < yc/h < 3.0 dengan debit per satuan lebar 69.13 cm2/det < q < 707.65 cm2/det. Hasil penelitian menunjukkan bahwa kehilangan energi relatif dapat dianalisis menjadi fungsi dari titik pemasukan udara, jumlah tangga, dan sudut kemiringan pelimpah, dalam bentuk (∆E1/E0) = a’ (Li/ks)b’Nc’ (sin θ)d’. Untuk debit yang merupakan fungsi dari bilangan Froude serta tinggi tangga sudah terinterpretasi dalam parameter titik pemasukan udara. Berdasar hasil perhitungan didapatkan koefisien determinasi pada tangga datar: R2 = 0.90 dan tangga menggunakan ambang: R2 = 0.79. Kesalahan relatif pada Rumus Krisnayanti ini diperoleh 1.87% untuk tangga datar dan 2.09% untuk tangga dengan ambang. Ini berarti analisis nilai kehilangan energi relatif bisa diperhitungkan dengan menggunakan titik pemasukan udara untuk perencanaan pelimpah bertangg
MEDIA KOMUNIKASI TEKNIK SIPIL, 2021
Temef Dam is located in Oenino Village Oenino District and Konbaki Village Polen District, Timor ... more Temef Dam is located in Oenino Village Oenino District and Konbaki Village Polen District, Timor Tengah Selatan Regency which has a capacity of 45.79 millions m3. This research aimed to determine the amount of potential evapotranspiration using Penman Modification Method, the amount of dependable discharge with three methods that are NRECA, F.J. Mock, and Tank Methods, from those three methods will be selected a method that have closest characteristic of Temef Watershed, and filling timein Temef Reservoir. The maximum half monthly potential evapotranspiration in Temef Watershed using Penman Modification Method is 142.72 mm and the minimum is 71,25 mm. The average of annual discharge using NRECA Method is 249.89 m3/sec, F.J. Mock Method is 258.66 m3/sec, and Tank Method is 92.15 m3/sec. Based from three methods that have been used, Tank Method is the closest method to the characteristics of Temef Watershed, which RMSE value from Tank Method is 2.99. Filling time of Temef Reservoir to...
Civil Engineering Journal, 2021
The Benanain Watershed is located in East Nusa Tenggara with an area of 3,181 km2 and is divided ... more The Benanain Watershed is located in East Nusa Tenggara with an area of 3,181 km2 and is divided into 29 sub-watersheds. The East Nusa Tenggara itself is an eastern region of Indonesia with a unique climate condition called semi-arid. The high rainfall intensity occurring in short duration results in large surface runoff and erosion. Floods and erosion in semi-arid areas due to sensitive soils to drought and heavy rainfall extremely. This paper presents the application of the Soil Conservation Services-Curve Number (SCS-CN) real-flood flows through a digital map of soil type, land use, topography, and the heterogeneity of physical condition, especially for ungauged watersheds. The method used is an approach empirical to estimate runoff from the relationship between rainfall, land use, and soil hydrology groups. This watershed has a large area that must analyze every sub-watershed. The land-use of the Benanain watershed is secondary dryland forest by 44.26% and the hydrological soil ...
IOP Conference Series: Earth and Environmental Science, 2021
Impacts of climate change have received extensive attention, especially for the semi-arid regions... more Impacts of climate change have received extensive attention, especially for the semi-arid regions. Raknamo reservoir is located at Kupang Regency, a semi-arid area with significant differences in rainy duration (3–4 months) and dry seasons (8–9 months). This preliminary study aimed to identify the recent factors that caused the delays in initial filling of Raknamo reservoir, which may be affected by climate change. There are three rainfall stations observed surrounding Raknamo watershed, namely Camplong, Naibonat and Raknamo. Direct comparisons were made of rainfall data for 33 years (1986-2019) daily. The climatology station Lasiana was used for climatological data with a data length of 33 years (1986-2019). This research used a qualitative approach, runoff was analyzed using regression analysis. The results showed that factors such as temperature (T), potential evapotranspiration (ETo), and rainfall (R) affected the availability of initial filling in the Raknamo reservoir. The amo...
Jurnal Teknik Pengairan, 2020
Kota Kupang dengan luas 180.27 km 2 , memiliki dua musim yaitu musim kemarau dan musim hujan. Kot... more Kota Kupang dengan luas 180.27 km 2 , memiliki dua musim yaitu musim kemarau dan musim hujan. Kota Kupang memiliki sembilan daerah irigasi yang terletak tersebar di Kota Kupang. Pada musim kemarau sering timbul kekeringan pada areal pertanian yang mengakibatkan gagal panen. Penelitian ini bertujuan untuk mengetahui pola tanam pada daerah irigasi di Kota Kupang yang optimal sesuai dengan keseimbangan air yang terjadi antara debit andalan dan kebutuhan air irigasi. Metode untuk menghitung evapotranspirasi digunakan metode Penman Modifikasi dan analisis debit andalan menggunakan metode F.J. Mock. Berdasarkan hasil penelitian, besar kebutuhan air irigasi yang terbesar adalah pada Daerah Irigasi Fatukoa untuk pola tanam padi-palawija-palawija sebesar 0.00-0.25 m 3 /dtk dan padi-padi-palawija sebesar 0.01-0.47 m 3 /dtk. Untuk neraca air Daerah Irigasi Fatukoa dengan pola tanam padi-palawija-palawija tahun normal (Q50) sebesar -0.25-2.39 m 3 /dtk dan tahun kering (Q80) sebesar -0.25-1.46 m 3 /dtk. Untuk sembilan daerah irigasi di Kota Kupang, pola tanam yang sesuai untuk tahun normal (Q50) adalah padi-palawija-palawija dan untuk tahun kering (Q80) adalah padi-palawija-palawija.
The watershed on Flores Island has the most diverse rivers stream in East Nusa Tenggara Province.... more The watershed on Flores Island has the most diverse rivers stream in East Nusa Tenggara Province. This causes the hydrological problems related to rivers stream pattern to be more complex. The aim of this study was to determine the characteristics of watersheds on Flores Island based on the shape of the watershed, drainage network density, and symmetrical factor. The object of this research was 38 watersheds data that the catchment area of 30 km 2 to 50,000 km 2 . The method used is the empirical method and using the GIS program. Based on the analysis using a Geographic Information System (GIS), there were 6 rivers of complex stream patterns, 14 forms of elongated storage, 10 forms of parallel, and 8 forms of radial. The results of the analysis obtained an average watershed area of 222,33 km 2 , an average river length of 30,48 km, an average drainage network density of 0.78 km 2 / km, and an average symmetrical factor of 0.65. Keywords : stream pattern, watershed, synthetic unit h...
Sabu Raijua is one of districts in East Nusa Tenggara province with dry climate that have annual ... more Sabu Raijua is one of districts in East Nusa Tenggara province with dry climate that have annual rainfall about 997 mm/year and including in low grade (<1500mm/year), with average evapotranspiration about7,259 mm/year. This causes required a water balance analysis in the district of Sabu Raijua.The method that used is a qualitative analysis that is obtained field data analysis and quantitative analysis that is obtained hydrology analysis and water balance analysis that used FJ Mock method and population analysis that used arithmetic method. The data accumulation is primary data (field measurements) and secondary data (rainfall data). This research purpose are show potential value, water demand, and water balance in the district of Sabu Raijua.Based on calculation show the potential value and water demandin the district of Sabu Raijua. The water blance show availability of water resources (assets) greater than water demand(liabilities) so that remaining balance of water is about75...
The functional design of infrastructures is generally determined by considering not only the phys... more The functional design of infrastructures is generally determined by considering not only the physical constraints of the location where the infrastructures are built but also the benefits those are going to be obtained. After infrastructures being constructed, the aforesaid functional design should be used as a basis to maintain further sustainability. During the service period of the infrastructures, the physical phenomena may be very dynamics that may affect the performance of the functional design. Under the normal and extreme condition, the functional design should be assessed continuously whether or not still performs as its previous condition, necessary analysis and update of related documents, e.g. the standard operating procedure are required. However, a structured monitoring system program should accompany the assessment. This paper deals with the assessment of the availability and release of water of Tilong Reservoir after about two decades of the construction. Assuming t...
Journal of the Civil Engineering Forum, 2021
Floods in a watershed area are caused by reduced water recharge due to changes in land use, incre... more Floods in a watershed area are caused by reduced water recharge due to changes in land use, increasing their discharge volume. Benanain watershed is an extensive area with many tributaries. Watershed morphometrics provides initial information about the hydrological behavior and the hydrograph shape of flooding in these areas. Furthermore, rainfall-runoff modeling uses as a unit to approach the hydrological values of the flooding process. This study determines the physical characteristics of the Benanain watershed based on curve number (CN) values, land cover, peak discharge, and peak time. It was conducted on the Benanain watershed with 29 sub-watersheds covering 3,181.521 km2. Data were collected on the rainfall experienced for 13 years from 1996 to 2008 and analyzed using the Log Pearson Type III method, while the HEC HMS model was used for flood discharge analysis. HEC-HMS model must calibrate by adjusting the model parameter values until the model results match historical data s...
AIP Conference Proceedings, 2020
Deterioration of water quality continues to be a major concern in West Timor. Establishment of wa... more Deterioration of water quality continues to be a major concern in West Timor. Establishment of wastewater treatment is crucial for eliminating this problem. Constructed wetland (CW) ecotechnologies are an alternative low-cost wastewater treatment to solve wastewater problems in West Timor. This research aimed to compare the effectiveness of Thypa latifolia in CWs for the removal of BOD 5 , suspended solids, NH 4 -N, and PO 4 -P. The experimental design consisted of 6 (20 L) vertical flow mesocosms, 3 mesocosms planted with Thypa latifolia and 3 mesocosms as a control. The mesocosms were irrigated with synthetic wastewater for 7 months. The inflow had a 2-day hydraulic retention time. The inflow and outflow samples were monitored for BOD 5 , suspended solids, NH 4 -N, and PO 4 -P. The trend showed that the CWs planted with Thypa latifolia reduced significantly the BOD, suspended solids, and NH 4 -N. However, the presence of plant did not significantly reduce PO 4 -P. This indicated that the CWs planted with Thypa latifolia had a better performance in comparison with pure sand media.
MEDIA KOMUNIKASI TEKNIK SIPIL, 2020
The impounding of the dam is the step that will be done after construction work on the dam be fin... more The impounding of the dam is the step that will be done after construction work on the dam be finished. This study aims to determine a long time and the volume of inflow on Raknamo dam in dry water year, low water year, normal water year and wet water year with tank model. Factors that affected the time of the first impounding of the dam is the amount of rainfall and evapotranspiration that has come in to the catchment area. The total volume of annual inflow Raknamo reservoir obtained in dry water year was in 15,489 million m3, low water year equal to 23,696 million m3, normal water year equal to 32,892 million m3 and wet water year equal to 44,068 million m3. In the calculation of the length of time filling the Raknamo reservoir used the volume of low water year. The accumulation of the volume of every month calculated so that length of time filling the Raknamo reservoir can reach the volume of planned at 14.091 million m3 within three a half months (three months fifteen days).
JURNAL SUMBER DAYA AIR, 2020
The construction of the Temef Dam in Oenino Village, Oenino District, and Konbaki Village, Polen ... more The construction of the Temef Dam in Oenino Village, Oenino District, and Konbaki Village, Polen District, South Central Timor Regency requires long and reliable rainfall data. To overcome the minimum data or the unavailability of automatic rainfall (ARR) and discharge data in the past decades, the use of Tropical Rainfall Measuring Mission (TRMM) satellite data is foreseen. The accuracy of TRMM data is obtained when the parameters of suitability and compatibility of TRMM are in a good agreement with the ARR. For the Temef watershed, there are six rainfall stations that were reviewed, namely Fatumnasi, Oeoh, Noelnoni, Polen, Nifukani, and Batinifukoko rainfall stations. Direct comparisons of rainfall data were conducted for 20 years (1998-2018) with temporal resolution on a monthly and daily basis. The results of the study show that the rainfall patterns in the TRMM data product (version 3B42V7) tend to be consistent with 3 rainfall stations in the Temef watershed namely Noelnoni, F...
IOP Conference Series: Earth and Environmental Science, 2020
Temef Watershed is located in the Benanain River Basin with a catchment area of 551.50 km2. River... more Temef Watershed is located in the Benanain River Basin with a catchment area of 551.50 km2. River characteristics in the Temef Watershed are influenced by three main river streams from upstream to downstream. Conventional collection of data on watershed characteristics requires a relatively long process and time. However, when based on Geographic Information Systems (GIS), the cost and time will be more efficient. The floodwater level is affected by the amount of rainwater runoff that occurs in the Temef Watershed. The amount of runoff depends on the level of soil permeability and land cover. To determine the level of soil permeability, hydrogeological maps are used. Based on this, a study of the characteristics of flood waters from GIS-based hydrogeology is needed. The analysis method used ArcGIS overlay on hydrogeological maps, while data on watershed characteristics used the Archydro and HEC-GeoHMS features. The results of the analysis showed a level 3 permeability type with lime...
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Papers by Denik Sri Krisnayanti