Soil Type Map Research Articles

Study of Yeh Embang Watershed Characteristics for Sustainable Water Management

One of Bali’s perennial watershed that is experiencing the effects of climate change is the Yeh Embang Watershed. If it is not managed holistically, the sustainability of the current water availability will be impacted. This research will analyse the Yeh Embang Watershed’s characteristics in order to evaluate the watershed’s condition and decide how to manage the sustainability of the water resources. For this research, topographic information, boundary maps of the Yeh Embang watershed, maps of river network, maps of land use, and maps of soil types were all used. The appropriate sustainable management for Yeh Embang Watershed should be determined based on the characteristic. According to the characteristics of the Yeh Embang Watershed, integrated management from upstream to downstream be necessary for the watershed to be managed sustainably. In the upstream area, it is hoped that the forest will be protected by forest conservation to reduce the risk of erosion that could lead to flash floods, and the downstream portion of the Yeh Embang watershed will be structured to prevent flooding from harming the surrounding area. Infiltration wells can be used as a water-saving measure in residential areas in the Yeh Embang watershed to increase the amount of water that is absorbed and lessen surface runoff.

Land Conservation and The Potential Goal for Food Security in Urban City

Population growth and increasing demand for land for urban development have led to the conversion of agricultural land. Land conversion harms the reduction of agricultural areas and indirectly affects food availability, so efforts are needed to preserve it. The study aims to obtain the availability of paddy fields and the conservation strategies. Evaluation of land use change and availability was analyzed by high-resolution SPOT 6/7 satellite imagery data, slope maps, soil type maps, sub-district administrative boundaries maps, raw rice field maps, spatial pattern planning maps, climate data, and criteria for land suitability for food crops. The strategy of conservation of paddy fields based on the wisdom of Subak (Balinese cultural base irrigation system for paddy fields) was analyzed by SWOT. The analysis showed that the converted land areas were 78.5 Ha. The available paddy fields that needed to be conserved were 895.02 Ha, consisting of a moderate suitability class of 556.74 Ha and a very suitable suitability level of 338.28 Ha. The strategy for conservation of paddy fields based on Subak wisdom must be implemented through 1) Developing tourist attractions based on Subak agricultural activities and rituals, 2) Developing a network of cooperation with the government and business people, 3) Implementing strict Subak rules (awig-awig), 4) Encouraging Subak to be more business-oriented through plant diversification that has market prospects.

A Study the Relationship of Soil Quality with Land Suitability for Coconut (Cocos nucifera L.) Development in Kebonagung Sub-district, Pacitan District

This study aims to assess the soil quality index (SQI) under the shade of coconut (Cocos nucifera L.) and its relationship to land suitability to provide recommendations for improvement to increase coconut productivity. This research conducted in Kebonagung District, Pacitan District using descriptive survey method. Land Map Units (LMU) are determined by overlaying soil type, land use, slope, and rainfall maps. Determination of survey using purposive sampling with 10 sample and three replications. The samples were analyzed in the laboratory with analysis method Bulk Density (Pycnometer), Porosity (Sample ring), Textures (Pipet), pH (Electrometric), Available P (Olsen method), Available K (NH4Oac 1 N extraction), Kjeldahl (Total N), Base saturation (Ammonium acetate extraction), SOC (Walkey and Black), CEC (Ammonium acetate method). Soil quality assessment was carried out using Principal Component Analysis (PCA) to obtain Minimum Data Sets (MDS). Land suitability was evaluated through the matching method with the conditions for growing coconut plants. The analysis showed that the soil quality index had a significant positive correlation with land suitability (r=0.768, p=0.004). The limiting indicators based on the correlation test were BV, pH, available P, organic C, and CEC. Suggested improvement recommendations include applying land cover crops, dolomite, manure, and balanced P fertilization.

Chemical Characteristics of Dryland Soils from Aceh Besar Regency As A Fertilizer Design Reference

Although the potential for dry agricultural land in Aceh Besar Regency is very wide, but the development of existing food crops is still low. There is a few information about the quality of soil chemical content in dry agricultural land effect to the development of crop productions. This study aims to provide information on the characteristics of soil chemical elements, Nitrogen, Phosphorus and Potassium on agricultural lands in Aceh Besar regency in the form of a map. This study was conducted using the analysis of variant tests method and spatial analysis. It covered some types of data, namely: Aceh Besar maps, administration data, soil type, topography and land use map that have been collected into a mapping of land use unit. The first stage in this study was collection of soil samples at predetermined location points with a depth of 0 to 30 cm and 30 to 60 cm. After the soil samples were obtained, analysis of Nitrogen, Phosphorus and Potassium elements in the soil chemical laboratory was carried out. The classification and factors found in soil chemistry analysis affected the content of Nitrogen, Phosphorus and Potassium in the soil. Analysis of variant tests showed that the type of soil did not have any influence on the content of Phosphorus and Potassium elements. While the sampling depth of 0 to 30 cm masked the impact on Nitrogen elements. On the other hand, land use only affected Phosphorus elements. Soil’s chemicals content had different levels. In this case, the value of Nitrogen content spread across 12 sampling points locations. as much as 91% of the available Nitrogen content is very low, while 50% of the available Phosphorous content is very low, then 8.3% of the available Potassium content were very low, and 25% of the available Potassium content were low. The mapping of soil chemical elements classification can provide information on the content of soil chemistry Nitrogen, Phosphorus and Potassium available in Aceh Besar Regency.

Study the Relationship of Soil Fertility with Land Suitability For Arabica Coffee (Coffea arabica L.) Development in Bandar Sub-district, Pacitan District

This study aims to assess the soil fertility index (SFI) under the shade of coffee and its relationship with land suitability to provide recommendations for improving arabica coffee productivity. This research was conducted in Bandar Sub-district, Pacitan District, East Java, using an exploratory, descriptive survey method. Land Map Units (LMU) are determined by overlaying soil type, land use, slope, and rainfall maps. Determination of survey points using purposive sampling with 10 sample points and three replications. The samples were analyzed in the laboratory to determine the soil’s physical, chemical, and biological characteristics. Soil quality assessment was carried out using Principal Component Analysis (PCA) to obtain Minimum Data Sets (MDS). Land suitability was evaluated through the matching method with the conditions for growing arabica coffee. The analysis showed that the soil fetility index had a significant positive correlation with land suitability (r=0.806, p=0.002). The limiting indicators based on the correlation test were SOC, pH, available P, and Base Saturation. Suggested improvement recommendations include applying land cover crops and balanced P fertilization.

Mapping the Groundwater Potential Areas by Using the GIS Method in Kg Samawang, Sandakan, Sabah, Malaysia.

This study aims to study the groundwater potential areas around Kg Samawang, Sandakan by using the Geographic Information System (GIS) method. There are few basic maps and data were used in this study, which is geology, drainage, soil type, lineament, topography, satellite images and rainfall distribution data. A total of seven thematic maps were produced including the lineament density map, drainage density map, landuse map, soil type map, rainfall distribution map, lithology map and topographic elevation map by using the ILWIS 3.0 software. All the thematic maps will be given a weightage based on its compensation to groundwater availability before being integrated based on the Hopkins Linear Equation using the Multi-Class Index Overlay model. This process will produce a forecast map of the groundwater potential at the study area. As a result of the forecast map, it is estimated that 40% of the study area has high potential of groundwater while 60% has medium, low and very low potential. It is hoped that this groundwater potential map can be used for the exploration work in the future.

LAJU INFILTRASI DAERAH BEKAS TAMBANG YANG DIPENGARUHI KARAKTERISTIK SIFAT FISIK TANAH

Infiltration is the process of entering water into the soil, infiltration capacity is the ability of the soil to absorb water per unit time. This study aims to determine the path of infiltration in the process of groundwater formation. This research was conducted in the Rumpin area, Bogor Regency, West Java Province. The method used in this study was carried out in two ways including collecting secondary data and primary data. Secondary data in the form of slope maps, rainfall maps. Primary data obtained from the results of field mapping (survey) and geology. The two data are correlated using the Geographic Information system so as to produce a map of the infiltration rate which has one unit which is sufficient, the soil type map, namely sand with poor gradation, the MAT map has three units, namely low, medium, adequate, the slope map has five units, namely very steep, steep, rather steep, sloping, flat, rainfall maps have one unit, namely height.

Determination of the Agricultural Land Potential Index Using a Geographic Information System: A Case Study of Aceh Tengah Regency, Indonesia

Agricultural problems that often arise are due to a lack of suitable and strategic agricultural land for its use, which results in poor agricultural production in the area. A land potential index that classifies existing land potentials from high to low class can be used to overcome this. This study aims to build an agricultural land potential index using a geographic information system in the Regency of Aceh Tengah, Indonesia, using a geographic information system. The method used in this research is a survey approach to collect information in the form of rainfall data, slope, lithology, soil type, land use and administrative maps of the Aceh Tengah Regency. The land potential index is obtained by overlaying the slope parameters, lithology, soil type, hydrology, and susceptibility to erosion into a land map unit that can classify it into five classes of a land potential index. The results of this study indicate that the Regency of Aceh Tengah is included in the very wet climate type. Maximum erosion was 1,213.6 tons per ha per year. The land potential index with very low criteria was 23.38% (102,002.42 ha) with a slope greater than 40%. The land potential index with very high criteria has an area of 3,807.80 ha (0.87%) with a maximum slope of 15%. A land potential index with very high criteria was found in the Linge, Atu Lintang, Lut Tawar, Pegasing, Bintang, Jagong Jeget, Kebayakan, Ketol, and Celala districts with an area of 2,014.26 ha, 1,266.33 ha, 174.81 ha, 148.07 ha, 77.86 ha, 73.63 ha, 46.77 ha, 4.14 ha and 1.94 ha, respectively. Meanwhile, the land potential index with very low criteria is found in all districts except Kute Panang and Atu Lintang.

Geomorphological Mapping for Land Suitability Evaluation

Geomorphology affects the potential of land. The geomorphological condition of an area has implications for physical characteristics, including: 1) type; 2) material; and 3) processes formed upon it. Understanding land capability allows for the evaluation of land suitability. Classification of land suitability is carried out by combining the results of land capability identification with requirements for plant growth or existing land use. Evaluation of land suitability can be done using the survey method. This study aimed to assess the suitability of land in Sumbersuko Village in Wagir District, Malang Regency. Land suitability was evaluated by matching the characteristics of the land with the land suitability class. This study used primary data taken from the regional morphology survey. Secondary data included: 1) digital elevation model data; 2) geological maps; 3) maps of soil types; and 4) Sentinel-2A images. The data from the field survey were then compiled using a geographic information system into maps using 2D and 3D modeling. The results of GIS analysis showed that Sumbersuko Village has six landform units, namely M1V1, M1V2, H2V2, U2V2, P2V2, and M3V3. Analysis of land capability and suitability of the six land units in a row gave the following results: 1) forest (highly suitable/S1); 2) forest and industry (suitable/S2); 3) plantation/agrotourism (moderately suitable /S3); 4) agriculture (not suitable/N); 5) residential area (less suitable/S3) S4); and 6) forest (highly suitable/S1).
 Keywords: scientific, approach, methodological, techniques, geography

Evaluation and improvement of rice field quality in Seririt District, Buleleng Regency, Bali Province, Indonesia

The decline of land quality has an impact on the decline of productivity which in turn reduces production. This kind of thing happened to rice fields in the research area of Seririt District. The objective of this study was to evaluate the rice field quality in Seririt District, Buleleng Regency, Bali Province. The study used a survey method to take soil samples, followed by laboratory analysis for each homogeneous land unit (HLU). The HLU was determined by overlapping soil type maps, slope maps, and utility maps. Parameters analysed were bulk density, texture, porosity, water content, organic C, pH, cation exchange capacity (CEC), base saturation (BS), nutrients (total N, available P, and available K), and biomass C. The results of the laboratory analysis were compared with the criteria for soil quality based on ten minimum data sets (MDS) for each HLU. The results showed that the soil quality at the study site is classified as very good in HLU I with a soil quality index (SQI) of 18. This HLU is located in Rangdu and Ringdikit villages, with an area of 125.15 ha. Good SQI was observed on HLUs II, III, IV, V, VII, and VIII, respectively, located in Banjar Asem, Lokapaksa, Pangkung Paruk, Bestala, Ume Anyar, Mayong, Joanyar, the SQI value of 22-25 is 2,321.49 ha with the limiting factors of total N, total P, texture, and bulk density. The suggested rice field management plan is the addition of organic, nitrogen, and phosphate fertilisers.

SAR-based Subsidence Monitoring and Assessment of the Factors Involved in the Occurrence of Subsidence, Lahore City

The judicious use and management of natural resources is vital to achieve sustainable development. Land and water are prime natural resources, and their depletion and degradation can lead to serious threats like land subsidence. Land subsidence is a phenomenon of the alteration of elevation at a point on the earth through the sinking of the surface. It occurs when the earth's surface loses its support. The major causes of land subsidence include groundwater extraction, mining, construction overload, and other similar factors that increase pressure on the surface and eventually subsidize the land. Urban centers with excessive groundwater extraction and infrastructure development are at a high risk of subsidence. Lahore, the second-largest city in Pakistan, is undergoing an enormous increase in population density, uncontrolled urbanization with very large-scale construction projects, and intensive groundwater extraction which are responsible for subsidence directly or indirectly. Therefore, studies on groundwater status and unplanned urban appraisals have seriously urged monitoring of the subsidence in Lahore. Herein, we used freely available Sentinel-1 data for one year (from August 2018 to August 2019), with a high spatial and temporal resolution, to monitor subsidence in Lahore. The data were processed using the SNAP/StaMPS approach for Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) analysis, which is an advanced InSAR technique. The displacement velocity map from InSAR processing shows a significant land deformation in the area with values ranging from –114 to 15 mm yr–1. Along with the Sentinel-1 data, we also used supplementary data obtained from various government agencies of Pakistan to study the land cover map, transportation network and waterways of Lahore, soil types, population density, and field points for assessing the results and understanding the roles of various factors in the occurrence of uplift or subsidence. A strong correlation was established between subsidence and various parameters such as groundwater extraction and lowering of the water table, soil type variations, land cover changes, surface water channels, and population density. The deformation map confirms the greatest subsidence in the central part of Lahore, while the uplift is observed in the less populated and rural areas situated near Ravi River. The land subsidence and uplift could be attributed to groundwater extraction and recharge through the canal system and the river, respectively.

ANALISIS PERKIRAAN DEBIT ALIRAN PADA DAERAH ALIRAN SUNGAI UNDA BERBASIS SISTEM INFORMASI GEOGRAFIS (SIG)

The limited flow data is an obstacle that often occurs in the analysis of water availability. To obtain this data, nowadays there are many prediction models for flow discharge. Remote sensing technology can improve the development of conventional rainfall–runoff relationship model studies. With this technology, it can help predict the runoff discharge for each Sub-watershed. The Unda watershed is one of the potential watersheds in the province of Bali. The flow discharge analysis was carried out using the overlay method by overlaying the land use map and the soil type map in the Unda watershed so as to obtain the CN value, then proceed with calculating the predicted flow rate using the SSCN method. From the analysis in the last ten years there have been fluctuations in discharge, where the largest discharge ever occurred was 10,569 m3/s in 2013 in the Telagawaja sub-watershed and the lowest was 0.079 m3/s in the Tanah sub-watershed in 2010. For the Telagawaja sub-watershed in the last ten years the average discharge -the average is 8.068 m3/s, Masin sub-watershed 0.963 m3/s, Tanah sub-watershed 0.163 m3/s, Nyuling sub-watershed 0.705 m3/s, Kaun sub-watershed 1.653 m3/s, Yeh Batah sub-watershed 0.564 m3/s Unda is 1.722 m3/s, and Sangsang sub-basin is 0.764 m3/s.

Land Suitability Evaluation on Pepper Plant in Bireuen Regency, Aceh Province

Pepper plant development requires data and information on land potential and land suitability class assessment based on the physical and chemical properties criteria so that the land can be productive. The study aimed to determine the land suitability class for pepper plants in Bireuen Regency. The research was conducted in Bireuen Regency. The unit land map (Satuan Peta Lahan, SPL) resulting from the overlay of the slope map, land use map, and soil type map was used in this study. The method used is a survey method with a land unit approach consisting of four stages: (1) preparation stage, (2) preliminary survey, (3) main survey, and (4) presentation of results. The results showed that the land had good to poor drainage, soil depth >75 cm, flat to steep slopes, mild to very heavy erosion hazard, dusty clay texture, low to high cation exchange capacity (CEC), slightly acidic to slightly alkaline pH, low organic C, Base Saturation (BS) is low to high, N total is low to very low, P2O5 is very low, and K2O is very low. Land suitability class for pepper plants in Bireuen Regency includes marginal suitability (S3) with limiting factors in the form of drainage, texture, CEC, BS, N-total, P2O5, K2O, slope, and erosion hazard. Improvements include making rorak, planting contours, drainage systems, applying manure or compost, and planting cover crops.

Studi Peningkatan Usia Guna Waduk Songputri Akibat Dampak Sedimentasi

Songputri Reservoir located in Wonogiri Regency which was built in 1977-1984 needs to be handled such as vegetation, checkdam construction, and dredging to find out how much additional the reservoir's useful life, besides that it is also necessary to calculate the erosion and sedimentation in the Songputri watershed. The data needed is monthly rainfall data, number of rainy days, and maximum daily data used to calculate the value of erosivity (R), a soil type map to determine the erodibility value (K), a slope map to determine the LS factor, and a land use map to determine the CP value. The calculations will using USLE method assisted by the ArcMap 10.4 application. From the results, it is known that the erosion is 23,157.57 tons/year, the sedimentation is 1,976.71 tons/year, and the reservoir useful life is 22 years. After that, reforestation is carried out on an area of 14.28 ha, construction of 6 checkdams, and dredging in the Songputri Reservoir. After that, the erosion and sedimentation were calculated using the same formula, it is known that the erosion is 7,735.39 tons/year, the sedimentation is 660.29 tons/year, and the useful life of the reservoir is increased to 67 years

Study on the potential of silica-available based on types of soil on the productivity of paddy field in West Java Province, Indonesia

The Si-available (Siap) content in the soil of paddy fields is decreasing, so it will affect decreasing the productivity of paddy fields. Soil type maps can be used to estimate the potential Siap content in paddy fields. The purpose of this study was to assess the productivity of the paddy field in West Java Province based on the Siap potential in each region using maps of soil types and paddy productivity data. This research was conducted in West Java Province. The research was carried out from February 2021 to March 2021. The research method used was the descriptive research method. This research is secondary data analysis so that no field test is carried out. The validation of the data from the analysis was based on the literature from the previous researchers. The parameters measured in this study were: the distribution of paddy fields, the percentage of soil types in each paddy field, the average productivity of paddy field on each type of soil, the distribution of paddy productivity levels, the potential for Siap to paddy productivity and map of the potential distribution of Siap in West Java Province. Secondary data obtained were then analyzed using spatial analysis and descriptive analysis. The results of the spatial analysis show that 77% of paddy fields in West Java have medium Siap potential, 17% low and 7% high. The results of the correlation analysis show that the productivity of paddy plants has a strong correlation (r = 0.99) to the Siap of paddy soil. The soil maps can be used to estimate the potential of Siap and the productivity of paddy plants. The Si application was recommended in paddy fields in the southern region of West Java Province.

INFLUÊNCIA DO USO E COBERTURA DA TERRA NA QUALIDADE DA ÁGUA DA BACIA HIDROGRÁFICA DO RIO UBERABINHA – MG

Este trabalho teve como objetivo analisar a influência do uso do solo no recurso hídrico da bacia hidrográfica do rio Uberabinha, localizada no município de Uberlândia / MG. Utilizando técnicas de geoprocessamento e sensoriamento remoto, foram elaborados mapas: uso do solo, hipsométrico, classe do solo e declividade. Foram utilizadas imagens do satélite LANDSAT 8 com resolução espacial de 30 m, de agosto de 2018, e do Modelo Digital de Elevação TOPODATA juntamente com os dados da série histórica de qualidade da água do rio Uberabinha, obtidos no IGAM - Instituto Mineiro de Gestão das Águas e o Ministério da Saúde. Os dados de qualidade da água foram referenciados de acordo com os limites estabelecidos pelo CONAMA - Conselho Nacional do Meio Ambiente e legislação internacional. A bacia do rio Uberabinha é ocupada predominantemente por áreas agrícolas. Quanto à qualidade da água referente ao ponto amostrado PB 023 localizado após dezesseis quilômetros da estação de tratamento de esgoto (ETE) da cidade de Uberlândia, as variáveis: coliformes totais, Escherichia Coli, sulfeto e fósforo apresentaram concentrações acima do valor limite estabelecido pela legislação, durante todo o período analisado. O uso do solo influenciou na contaminação da água da bacia hidrográfica, especialmente, no percurso que envolve a malha urbana de Uberlândia.

Prediction of Erosion and Sedimentation in Micro Catchment Area of Air Lanang Using Soil and Water Assessment Tool (SWAT) Model

This research aims to obtain erosion and sedimentation rate data in the micro catchment area of Air Lanang using soil and water assessment tool (SWAT) modelling within existing and scenario land uses. Geographically, the study area is located between latitude 3°26`23.48” - 3°31`46.09” S and longitude 102°24`11.74” - 102°28`26.35” E with a total area of 2987.06 ha. Soil analysis was conducted in the Soil Science Laboratory, Faculty of Agriculture, University of Bengkulu. The research data was analysed using SWAT model. Recorded data in this study were including soil analysis data, soil type map from land unit and soil map book Bengkulu sheet (0912) Sumatra, data of status area from KLHK, Digital Elevation Model National data from BIG, a set of climate data from BMKG, data of administrative border from RBI map Bengkulu Province and data of land use from the interpretation of satellite image and ground checking, as well as the scenario land use which was prepared following the community forest program from the government in the protected forest by converting the coffee plantation located within the protected forest area to woody plants with economic, social and conservative values. The results showed total erosion in the micro catchment area of Air Lanang with the existing land use in 2020 was 820731.87 ton year-1, while in the scenario land use was 288212.45 ton/year which were classified to very light, light, moderate, heavy and very heavy in class erosion. Based on the existing land use data, there was a decrease of erosion in the moderate to very heavy class of erosion for 7.27 % resulting in the very light and light class of erosion become 15.55 % after the simulation of the scenario land use model. The use of scenario land use model is effective to decrease erosion and sedimentation rate. The total sedimentation in the micro catchment area of Air Lanang in existing land use in 2020 was 354949.98 ton year-1 with the highest sedimentation in sub-basin 2 while the lowest sedimentation was found in sub-basin 12. On the other hand, the total sedimentation in the scenario land use model was 137365.04 ton year-1. The reduction of total sedimentation in existing land use in 2020 to the scenario land use model was 36.76 %.

Sub-Surface Geotechnical Data Visualization of Inaccessible Sites Using GIS

Geotechnical investigation, in hilly areas, for high-rise projects, becomes a problematic issue and costly process due to difficulties in mobilization and assembling the drilling equipment on mountainous terrains. The objective of this study is to map soil properties of study areas, especially at inaccessible sites, for reconnaissance. Digital soil maps for Tehsil Murree, Pakistan, have been developed using the emerging Geographical Information System (GIS). The research work involved the creation of an exhaustive database, by collecting and rectifying geotechnical data, followed by the digitization of the acquired data through integration with GIS, in an attempt to visualize, analyze and interpret the collected geotechnical information spatially. The soil data of 205 explanatory holes were collected from the available geotechnical investigation (GI) reports. The collection depth of soil samples, which were initially used for the design of deep and shallow foundations by different soil consultancies in the Murree area, was approximately 50 ft. below ground level. Appropriate spatial interpolation methods (i.e., the Kriging) were applied for the preparation of smooth surface maps of soil standard penetration tester number values, soil type and plasticity index. The accuracy of developed SPT N value and plasticity maps were then evaluated using the linear regression method, in which the predicted values of soil characteristics from developed maps and actual values were compared. SPT N value maps were developed up to a depth of 9.14 m below ground level and at every 1.52 m interval. The depth of refusal was considered in the developed maps. Soil type and plasticity maps were generated up to 15.24 m depth, again at every 1.52 m intervals, using color contours, considering the maximum predicted foundation depth for high-rise projects. The study has implications for academics and practitioners to map the soil properties for inaccessible sites using GIS, as the resulting maps have high accuracy.

Analisis Dan Simulasi Banjir Das Kenali Kecil Dengan Menggunakan Sig Dan Model Hidraulika Hec-Ras

Floods are the most common disasters in almost all places, including Indonesia and Jambi City in particular. Areas that are directly affected by the threat of flooding are in the Watershed. Kenali Kecil watershed is one of the sub- watersheds of Batanghari which is administratively located in Jambi City and Muaro Jambi Regency. The Kenali Kecil watershed is influenced by the rapid growth of Jambi City. Land conversion is not the only cause of flooding in the Kenali Kecil watershed. Floods also occur because the discharge/volume of water flowing in a river or drainage system exceeds its drainage capacity. This study analyzes the level of flood vulnerability based on SNI 8197:2015 and Head of BNPB Regulation No. 02 of 2012. The approach used in the SNI method is landscape analysis which emphasizes the process of forming natural systems on the earth's surface. Analysis of the level of flood vulnerability based on the Regulation of the Head of BNPB is based on the results of flood simulations using the HEC-RAS hydraulic model. The parameters used in this model are the manning’s coefficient, data geometry, discharge plan and terrain. The terrain used in this research is DEMNas. Discharge plan are obtained using the HEC-HMS application. In making the discharge plan, rainfall data for the last 10 years is needed, to get the CN and Impervious values, soil type maps and land use maps are needed. Based on the procedure of Indonesian National Standard (SNI) 8197:2015) the level of flood vulnerability in the Kenali Kecil watershed is in the medium level of 8.25 km2 (52.6%) and high level of 7.43 km2 (47.4%). Based on the HEC-RAS modeling for the 2-year return period (Q2), the flood area is 1.08 km2, the 5-year return period (Q5) is 1.2 km2 and the 10-year return period (Q10) is 1.3 km2. Based on the Regulation of the Head of BNPB No. 02 of 2012 the flood vulnerability level of the Kenali Kecil watershed is in the low level (<0.76) Q2 = 0.33 km2, Q5 = 0.31 km2, Q10 = 0.32 km2, medium level (0.76 – 1 ,5) Q2 = 0.32 km2, Q5 = 0.31 km2, Q10 = 0.34 km2 and high level (> 1.5) Q2 = 0.43 km2, Q5 = 0.58 km2, Q10 = 0.64 km2

Analysis Distribution of Biomass Carbon of Grasslands, Shrubs, and Rainfed Rice Fields on Dry Land in the Aceh Besar District Indonesia

Abstract This research was conducted to determine plant biomass, carbon potential, and CO2 reserve potential in understory vegetation in general, namely grasslands, shrubs, and rainfed rice fields. The sampling of the research was carried out randomly and intentionally, and was limited to the vegetation of reeds, shrubs and rainfed land bushes in the Aceh Besar District of Indonesia. The sample was taken based on a digitized map obtained from overlaying the land use map, slope map, soil type map, and Aceh Besar government map. Measurement of biomass in the vegetation of Imperata, shrubs, and rainfed rice fields is in accordance with procedures from the Indonesian National Standard (2011) and the World Agroforestry Center. The area of bush vegetation is larger than that of rainfed rice fields and grasslands. In general, the plants found in bush vegetation are Acacia leucoeplhoea, Mimosa pudica, Cyperus rotundus, and Eleusine indica. Grassland vegetation has one plant only, namely, Pennisetum purpureum. The vegetation of rainfed rice fields consists of the Oryza sativa type of plant. Plant biomass, carbon [C] content, and carbon potential in bush vegetation are greater than that of grassland and rainfed rice fields, as well as plant biomass reserves, plant biomass carbon and total CO2 reserves. Shrubs and woody plants render the potential for biomass, carbon, and CO2 absorption greater than that of grassland and rainfed rice fields. This is in accordance with the research that the increase in biomass is followed by an increase in potential carbon storage. Parameters that affect biomass indirectly will also affect carbon storage in a biomass and in an ecosystem, namely, individual density, stem diameter, tree species diversity, and soil. The density of trees in an area will affect the increase in carbon stocks through an increase in biomass. This is because the vegetation of shrubs does not only consist of undergrowth, but also of woody stems such as Acacia leucoeploea, making carbon stock potential in bush vegetation greater than that of grassland and rainfed rice fields, as shrubs cover an area of 96,962.2 ha, hence larger than that of grasslands and rainfed rice fields.