• Title/Summary/Keyword: water yield

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Evaluation of hydropower dam water supply capacity (II): estimation of water supply yield range of hydropower dams considering probabilistic inflow (발전용댐 이수능력 평가 연구(II): 확률론적 유입량을 고려한 발전용댐 용수공급능력 범위 산정)

  • Jeong, Gimoon;Kang, Doosun;Kim, Dong Hyun;Lee, Seung Oh;Kim, Taesoon
    • Journal of Korea Water Resources Association
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    • v.55 no.7
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    • pp.515-529
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    • 2022
  • Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.

Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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Evaluation of the Spatial Distribution of Water Yield Service based on Precipitation and Population (강수량 및 인구인자를 반영한 수원함양서비스의 공간분포 평가)

  • CHO, Heun-Woo;SONG, Chol-Ho;JEON, Seong-Woo;KIM, Joon-Soon;LEE, Woo-Kyun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.3
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    • pp.1-15
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    • 2016
  • The study of ecosystem service assessment has been actively researched and developed from Millennium Ecosystem Assessment(MA) and The Economics of Ecosystems and Biodiversity(TEEB). However, current assessments are limited to monetary assessments of ecosystem function and do not account for the effects of environmental factors and socioeconomic status. This study proposes methods to evaluate ecosystem service based on environmental and socioeconomic factors. The study assesses water yield function through the water yield model in InVEST Tool, and evaluates the overall ecosystem service of water yield as reflected by the amount of precipitation and population of the area. Results show that a difference exists between spatial distributions of the ecosystem function of water yield derived from natural conditions such as land cover and soil, and the spatial distribution of the ecosystem service that accounts for climate and socioeconomic factors. The value of ecosystem service increases for an area of higher population and lower precipitation with similar water yield. Thus, the ecosystem service of water yield should be evaluated not only by the water yield function, but also by climate and socioeconomic factors. The evaluation process described for this study should also be applicable to the evaluation of ecological services in other sectors.

Soybean Yield Performance and Growth Characteristics in Response to Underground Water Table Depth (지하수위에 따른 콩 품종의 생육특성 및 수량반응)

  • 윤광일;이홍석
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.3
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    • pp.367-372
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    • 1997
  • Excessive water stress is one of major limiting factors affecting soybean yield, especially when soybean is grown in converted upland from paddy field. The present study was undertaken to know the genotypic variation in yield response of soybean to different environments in combination with soil texture and underground water table depth. Eight recommended soybean varieties in Korea and two supernodulating soybean mutants introduced from USA were planted in the lysimeter which was filled with two different soil types(sandy loam and clay loam). Of three underground water table depths(10, 30, and 50 cm) during whole growth stage, the lowest 10 cm was included to create excessive water stress. Yield was significantly different according to the underground water table depth and soybean genotypes, whereas soil type did not affect yield. There were significant interaction effects of soybean yield among soil type, soybean genotype, and underground water table depth. Yield of nts 1116 showed the highest across environments. Based on the regression analysis, the most stable variety was Sobaeknamulkong(bi=1.09). Jangsukong was fairly stable and high in yield, when compared to other soybean genotypes. However, nts 1116 was the most desirable ($D_i=228$) mainly due to the highest yield rather than the greater stability over environments. Multiple regression analysis revealed that shoot dry weight and nodule number were major factors affecting yield in the combined data over three water table depths and two soil types.

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Water yield estimation of the Bagmati basin of Nepal using GIS based InVEST model (GIS기반 InVEST모형을 이용한 네팔 Bagmati유역의 물생산량 산정)

  • Bastola, Shiksha;Seong, Yeon Jeong;Lee, Sang Hyup;Jung, Younghun
    • Journal of Korea Water Resources Association
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    • v.52 no.9
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    • pp.637-645
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    • 2019
  • Among various ecosystem services provided by the basin, this study deals with water yield (WY) estimation in the Bagmati basin of Nepal. Maps of where water used for different facilities like water supply, irrigation, hydropower etc. are generated helps planning and management of facilities. These maps also help to avoid unintended impacts on provision and production of services. Several studies have focused on the provision of ecosystem services (ES) on the basin. Most of the studies have are primarily focused on carbon storage and drinking water supply. Meanwhile, none of the studies has specifically highlighted water yield distribution on sub-basin scale and as per land use types in the Bagmati basin of Nepal. Thus, this study was originated with an aim to compute the total WY of the basin along with computation on a sub-basin scale and to study the WY capacity of different landuse types of the basin. For the study, InVEST water yield model, a popular model for ecosystem service assessment based on Budyko hydrological method is used along with ArcGIS. The result shows water yield per hectare is highest on sub-basin 5 ($15216.32m^3/ha$) and lowest on sub-basin 6 ($10847.15m^3/ha$). Likewise, built-up landuse has highest WY capacity followed by grassland and agricultural area. The sub-basin wise and LULC specific WY estimations are expected to provide scenarios for development of interrelated services on local scales. Also, these estimations are expected to promote sustainable land use policies and interrelated water management services.

An Evaluation Study on Total Nitrogen(T-N) Item of Agricultural Water Standards (농업용수 수질기준 T-N 항목에 대한 검증 실험( I ))

  • Choi, Seon-Hwa;Kim, Ho-Il;Kim, Min-Ho;Lee, Byeon-U;Lee, Bong-Hun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.1
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    • pp.99-105
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    • 2004
  • The present agricultural water quality standards are set by a policy goal. This is intended for water quality management of public water resources, but not for the use of water resources. These standards were not determined by considering the influence of water quality on the safety of agricultural produce and the growth, yield and quality of agricultural crops. Thus, this study was carried out to investigate the influence of irrigation water quality on the growth, yield, and grain quality of rice and acquire fundamental knowledges to set up irrigation water quality standards. The pot experiment was conducted with 4 treatments using irrigation waters with various total nitrogen concentrations (control, 1, 5, 10, 20mg/L) and replicated four times with randomized block design. The results of this study showed that plant height, number of tiller, plant dry weight, the uptake of N, P, and K, and rice protein contents tended to increase as the T-N concentration in irrigation water was increased. In addition, grain yield at T-N 20 mg/L was significantly higher than in the control, but the percentage of head rice was slightly lower due to the increase of green kernel and white belly/core kernel.

Cocoon Yield Pattern and Analysis of Water, Soil and Leaves from Mulberry Gardens Irrigated with Polluted Water Around Bangalore, India

  • Chandrakala, M.V.;Maribashetty, V.G.;Aftab Ahamed, C.A.;Jyothi, H.K.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.18 no.2
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    • pp.97-103
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    • 2009
  • Sericulturists in the vicinity of Bangalore city irrigate their mulberry gardens with Vrishabhavathy stream water, which is polluted with domestic and industrial wastes from the city. To investigate the effect of pollutants on silkworm crops, a detailed field survey was conducted to study the cocoon yield pattern of the crops raised on mulberry irrigated with wastewater as against irrigation by bore/open wells. The villages along the stream were grouped into five test batches at about a distance of $5{\sim}8$ km from each other. The seasonal yield data with relevant information were collected through questionnaires from 117 rearers using stream water and 35 rearers using bore/open wells, the latter serving as control group. The average yield for 100 layings was 46 to 57 kg in the control group whereas in test groups, it ranged between 34 to 51 kg in the first test group and 22 to 38 kg in the rest. The difference in yield was $9{\sim}19$ kg depending on the season between control and test batches. In summer, this difference was higher, with high co-efficient of variation in test groups ($33{\sim}52$%). Further, water, soil and leaf samples were collected from selected rearers and were analyzed for zinc, copper, iron, lead and nickel. Results indicated significantly higher contents of these metals in samples from gardens using wastewater when compared control samples. Significantly (p<0.05 & p<0.01)) higher levels of zinc ($24{\sim}122$ ppm) and iron ($208{\sim}683$ ppm) were noticed in mulberry leaves during summer followed by winter and rainy season. The significance of high content of heavy metals in mulberry leaves and cocoon yield pattern of this area in relation to the quality of irrigation water is discussed.

Effects of Desalinization Management on Rice Yield in Sea Water Flooded Field

  • Kim, Sang-Su;Yang, Won-Ha;Choi, Weon-Young;Park, Hong-Kyu;Choi, Min-Gyu;Back, Nam-Hyun;Kang, Si-Yong;Shin, Hyun-Tak;Cho, Soo-Yeon;Kwon, Seog-Ju;Ko, Bok-Rae
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.44 no.1
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    • pp.38-43
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    • 1999
  • Over 2,000 ha of rice fields in the western and southern coastal region of Korea were flooded with sea water during the spring tide, on August 19-21, 1997, and the rice plant at heading stage was injured. The field surveys were undertaken at the sea water flooded paddy fields in Chonbuk Province, to identify the injury symptoms and rice yield damage subjected to different flooding condition and desalinization methods. Five days after sea water flooding at heading stage, the flag leaves of rice plants flooded with 30 ㎝ deep sea water withered from the tip, the withering progressed to the lower leaves in deeper flooding. The spikelets were spotted black and discolored from the tip at 50 ㎝ deep flooded rice, and some panicles changed to white at 80 ㎝ deep flooded rice. Most of the rice leaves submerged completely for an hour were withered and most of panicles changed to white. The milled rice yield, percentage of ripened grain, and 1000 grain weight of flooded rice decreased with deeper flooding water, higher water salinity and longer flooding time. Even under the same flooding conditions, the damage of rice yield varied with the growth stage: heading stage>dough stage>booting stage. Rice yield damage was less in the fields on the upper riverside than those of the fields on the estuary and seaside, because of lower water salinity. In a flooded field, the rice yield damages were reduced as the distance increased from the levees where the sea water inflowed and increased as the distance increased from the fresh water irrigation gate. The desalinization treatments consisting of frequent exchange of irrigation water and spraying with fresh water soon after flooding effectively reduced the rice yield damage.

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Water saving irrigation method in paddy fields (용수절약형 논관개 기법(관개배수 \circled1))

  • 정상옥;안태홍
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2000.10a
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    • pp.108-113
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    • 2000
  • A field study was performed to investigate the effect of water saving irrigation method on water use efficiency and rice yield. The field plot was 40a (40 ${\times}$ 100m) in size and located at Buryangmyun, Kimjae city, Chonbuk province. Field measurements were made during the growing seasons, May to September of the year 1998 and 1990. Irrigation water volume, drainage water volume, rainfall and ponding depth were measured. Irrigation water management practice employed was such that to keep the ponding depth about 3 to 4cm by intermittent irrigation with drying the soil surface until hair cracks emerge before the next irrigation. The amounts of water volume irrigated and drained were measured by pipe flow meter and ponding depth was observed by using a partly buried 120mm diameter PVC pipe. The results showed that the irrigation water depths, the rainfalls, and the drainage depths were 379mm, 458mm, and 448mm in 1988, and 274mm, 819mm, and 736mm in 1990, respectively. The average yield was 590kg per 10a. The water saving irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method.

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Evaluation of impact of climate variability on water resources and yield capacity of selected reservoirs in the north central Nigeria

  • Salami, Adebayo Wahab;Ibrahim, Habibat;Sojobi, Adebayo Olatunbosun
    • Environmental Engineering Research
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    • v.20 no.3
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    • pp.290-297
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    • 2015
  • This paper presents the evaluation of the impact of climate change on water resources and yield capacity of Asa and Kampe reservoirs. Trend analysis of mean temperature, runoff, rainfall and evapotranspiration was carried out using Mann Kendall and Sen's slope, while runoff was modeled as a function of temperature, rainfall and evapotranspiration using Artificial Neural Networks (ANN). Rainfall and runoff exhibited positive trends at the two dam sites and their upstream while forecasted ten-year runoff displayed increasing positive trend which indicates high reservoir inflow. The reservoir yield capacity estimated with the ANN forecasted runoff was higher by about 38% and 17% compared to that obtained with historical runoff at Asa and Kampe respectively. This is an indication that there is tendency for water resources of the reservoir to increase and thus more water will be available for water supply and irrigation to ensure food security.