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1.
Most flood damage in Korea is caused by heavy rainfall events and typhoons during the summer rainy season. A modified Natural Resources Conservation Service (NRCS) TR-20 model, TR-20-RICE, was developed to investigate the storm runoff characteristics of a 385-ha mixed-landuse watershed in Korea. The TR-20-RICE not only used the rainfall excess and hydrologic flood routing components of the original TR-20 model, but also included a paddy runoff process, which captured irrigated paddy runoff characteristics such as inundation, retention storage, and surface runoff. The performances of TR-20 and TR-20-RICE were compared using storm hydrographs and observational data. The results indicated that both models simulated storm runoff accurately over the simulation period. The TR-20-RICE runoff volume, peak discharge, and time-to-peak predictions were slightly closer to observations than those of the TR-20. The TR-20-RICE model may an effective alternative to the TR-20 model for generating storm hydrographs, particularly in the mixed-landuse watershed in Korea.  相似文献   

2.
为分析半干旱区低影响开发建设对城市河流水文系统的可能影响,应用暴雨洪水管理模型(SWMM)和河段水量平衡模型,以秦岭北麓灞河流域为例,对不同重现期及典型降雨过程的降雨径流过程进行模拟计算,并对不同LID措施的流域洪峰、洪量、河流水量、水流流速等量值变化及可能的水质环境影响进行分析。结果表明:考虑LID措施的流域暴雨洪水计算中,重现期越长,河道内洪峰、洪水总量消减比例越小。设计暴雨重现期小于10年的洪水消减比例最大;流域内城市区低影响开发建设后,滨河带地下水补给量减少;LID措施后径流量减少,可能加重下游水污染。研究揭示了半干旱地区低影响开发建设的河流水文系统变化特征及其可能引起的水环境问题,对更合理地开展城市雨洪管理工作具有指导意义。  相似文献   

3.
为探求从化市水南村部分农田被淹没的主要原因,本文对水南村所在小流域的降雨资料和涌容关系进行了分析。在对流溪河洪水特性和牛心岭电站操作对淹没位置河段水位影响分析的基础上,真实反演出了部分农田被淹没的过程。结果显示,在不考虑淹没区涵洞排水的条件下,采用大坳站和太平场站的平均雨量资料,本次降雨造成淹没区的水位上涨幅度可达2.74 m;淹没区水位经历了两次上涨,第一次主要由产汇流太急造成涵洞排水不及造成,第二次主要是流溪河洪水上涨造成涵洞无法排水所致。未封堵暗渠导致了流溪河洪水倒灌入淹没区,造成最大淹没深度为0.23 m;牛心岭电站操作对淹没区影响较小。  相似文献   

4.
Given a suitable high and constant temperature regime, rice can be cultivated year-round in the tropics as long as water is available. Accordingly, multiple cropping is possible in such regions. The number of croppings per year varies depending on water availability and thus annual gross cultivated acreages are subject to fluctuation. The predominant causes of this fluctuation are related to seasonal and inter-annual variability in the volume of precipitation along with the hydrological characteristics of the watershed. We analyzed the effect of preceding precipitation on cultivated paddy field acreage in the Cidanau watershed, West Java, Indonesia. The analyses had two steps; first, the manipulation of eight Landsat images of different years to identify paddy fields cultivated in the entire paddy field area. There was difficulty in identifying cultivated paddy fields because of the coexistence of various growth stages of rice; however, early growth stage paddy fields were successfully distinguished from uncultivated fields using middle infrared band values due to surface reflectance of flooded water, while more advanced growth stage fields were identified with Normalized Difference Vegetation Index values. The second step was implementation of a linear regression model to the cultivated paddy field ratio with the cumulative volume of preceding rainfall as a single independent variable. The result confirmed that there was a strong correlation between 90-day cumulative rainfall and cultivated paddy field acreage as identified by satellite images, where “90-days” implies the lifespan of paddy rice after transplantation. However, the sensitivity of cultivated paddy fields to the preceding rainfall ratio varied among sub-watersheds due to variations of hydrological characteristics and the storage capacity of the particular water source.  相似文献   

5.
The objective of this study was to estimate irrigation return flow in irrigated paddy fields considering the soil moisture. The proposed model was applied to examine its feasibility with regard to the growing period of rice. Simulation results showed a good agreement between the observed and simulated values: root mean square error (RMSE) of 6.05-7.27 mm day−1, coefficient of determination (R2) of 0.72-0.73, and coefficient of efficiency (E) of 0.54-0.55. The estimated average annual irrigation return flow during the period from 1998 to 2001 was 306.2 mm, which was approximately 25.7% of the annual irrigation amounts. Of this annual irrigation return flow, 14.1% was attributable to quick and 11.6% to delayed return flow. These results indicate that considerable amounts of irrigation water in the paddy fields were returned to streams and canals by surface runoff and groundwater discharge. The modeling assessment method proposed in this study can be used to manage agriculture water and estimate irrigation return flow under different hydrological and water management conditions.  相似文献   

6.
王家厂水库洪水实时预报方法及应用研究   总被引：1，自引：1，他引：1  
考虑到流域降雨时空变化和流域地形、河道特征对流域产汇流的影响，应用新安江三水源产流模型、流域分散入流非线性汇流模型以及流域洪水实时预报校正模型，对王家厂流域洪水进行模拟，取得了较为满意的计算结果。  相似文献   

7.
山洪灾害往往给山区人民生命财产、自然环境等造成了极大的损害,降低山洪灾害的有效途径之一是实现基于降雨径流模型的实时预报预警系统。选取四川省山洪易发流域-清溪河流域为研究区,通过GIS技术,结合流域DEM、土壤及土地利用数据提取流域信息,构建HEC-HMS降雨-径流模型进行流域山洪预报。根据降雨径流形成过程,分别采用SCS-CN曲线法、SCS单位线法、指数退水法和马斯京根法进行计算产流、坡面汇流、基流和河道汇流四个部分。选取6场洪水进行模型参数的率定,4场洪水进行模型验证。模拟结果表明:Nash效率系数均值为0.792,相关系数均值为0.84,峰现时差均在3 h以内,合格率为90%,该模型对清溪河山洪预报具有较好适应性,可为四川省中小河流域山洪预报提供借鉴和参考。  相似文献   

8.
【目的】研究土地利用方式变化对排涝模数的影响,优化区域排涝管理。【方法】选取湖北四湖流域螺山排区为研究区域,将流域水文模型SWAT和土地利用变化模型CLUE-S联合应用,设置了6种水旱比、5种水面率及5种城市化率的单因素变化(即其他2个因素不发生变化)条件下不同土地利用情景,应用CLUE-S模型模拟生成各情景下的土地利用空间分布图,建立了SWAT模型模拟不同土地利用情景的降雨径流过程,分析了不同土地利用方式对排涝模数的影响。【结果】在相同的设计暴雨、其他因素维持现状条件下:当水旱比由0增加到1时,排涝模数减小了0.117 m~3/(s·km~2);当水面率由0增加到20%时,排涝模数减小了0.111 m~3/(s·km~2);当城市化率由0增加到10%时,排涝模数增加了0.104 m~3/(s·km~2)。排涝模数随着水旱比和水面率的增大均呈减小趋势,随着城市化率的增大呈增大趋势。在相同设计暴雨、其他因素维持现状条件下:当水旱比由0增加到0.2时,排涝模数只减小了3.06%;当水面率由0增加到10%时,排涝模数减小了14.03%;当城市化率由0增大到10%时,排涝模数增大了16.67%。3种引起土地利用方式变化的因素中,排涝模数对水面率和城市化率变化的敏感程度相当,对二者的敏感程度明显大于水旱比。【结论】在未来区域规划中,可以通过增大水旱比、增大水面面积和限制城市扩张来减轻排涝压力,其中适当增大水面面积和限制城市扩张更加有效。  相似文献   

9.
Excessive nutrient loadings from rice paddy fields has been a great concern in Korea as rice paddy area spans over 1,153,000 ha, which covers approximately 60% of the total agricultural land area in Korea. The principal tasks of this study included undertaking work to better identifying the scope of the nutrient loadings from paddy fields to assess their adverse effects. Hydro-meteorological factors, rainfall and surface discharge, were considered as the major driving forces of nutrients into the water. A Generalized Regression Neural Network (GRNN) model was applied and its capability evaluated to predict the nutrient loading into the neighboring water. The 15 ha paddy fields surrounded by drainage and irrigation channels were chosen as a study area. Field data, such as rainfall, quantities of irrigation and discharge water, and nutrient contents (total nitrogen (T-N) and total phosphorus (T-P)) from two different water sources, were obtained throughout the study period. Simulation results showed that surface discharge had a positive correlation with rainfall (R = 0.84). In addition, the resulting predictions for nutrient concentrations corresponding to surface discharge were varied (R = 0.72 and 0.40 in total nitrogen and total phosphorus, respectively). This study found that both natural and artificial variations of nutrient contents in irrigation streams were significantly influenced the model results of nutrient predictions. Therefore, the nutrient loadings into the neighboring water can be accurately described with a more comprehensive and sufficient representation of both environmental inputs and hydrological processes.  相似文献   

10.
This paper investigates the impacts of farm ponds in a context of declining supplies in a major canal command within the Zhanghe Irrigation System (ZIS), in Central China. As dam supplies have been diverted to higher-valued uses (hydropower, cities and industry), farmers have responded by constructing small storages within their fields. These farm ponds have given them sufficient flexibility in water supply to practice varying forms of alternate wetting and drying irrigation for rice without compromising yields and incomes. Ponds are recharged by a combination of return flows from irrigation and runoff from catchment areas within the irrigated perimeter. Various scenarios of water supply incorporating the main reservoir, in-system reservoirs, farm ponds and irrigation practices were simulated using the OASIS model. OASIS integrates surface and groundwater flows, and contains a crop growth module to aggregate the impacts of different water management regimes. The modelling and sensitivity analysis show that further reductions in main reservoir supplies will have a negative effect on rice production in dry and average years, and that ponds have played a crucial role in adapting agriculture to reduced canal supplies. The flexibility allowed by the ponds has resulted in increased water productivity, except in high rainfall years, but net depletion has not decreased, as local supplies have substituted for water from the main reservoir. The study demonstrates the importance of properly accounting for return flows and the necessity to understand crop production in relation to the actual depletion of water (as evapotranspiration) within an irrigation system.  相似文献   

11.
Flow regimes of water draining from replicated mole drained and undrained plots under different cultivation systems were examined in a 10-year study. In 9 out of 10 years, winter cereals were grown with all residues removed by burning. One crop of oil-seed rape was sown in 1985. A 2 year uniformity trial at the start of the experiment, when all plots were tine cultivated, showed that a cultivation pan exerted an important influence on soil-drainage and water movement. Once removed, effective subsurface drainage increased the depth to the water-table by an average of 215 mm over the winter, with up to 90% of the flow occurring through the mole drains. Following the imposition of differential cultivations in 1980, no discernible change in runoff was observed on plots under ploughing compared to the previous tine cultivations. In contrast, direct drilling caused higher surface runoff than ploughing due to surface compaction, although better subsoil structure development led to more rapid vertical movement of water, and especially in the years following mole drainage an increased peak drain-flow of up to 30%. Although drainage decreased the overall flood risk by as much as 16% in a 10 year return period event, cultivations were of considerable importance and direct drilling increased peak runoff by at least 70% from both drained and undrained plots.  相似文献   

12.
为了解华南花岗岩小流域特殊的产流机制,以土壤为砂壤土、基岩为强风化花岗岩的中山大学珠海校区滨海小流域作为研究对象,观测了2个分别代表森林、灌丛覆盖的5 m×10 m的径流试验场的产流过程和土壤含水率变化过程。观测结果表明超渗产流、优先流是试验场的重要产流方式,壤中流（尤其是在土壤-基岩界面上产生的壤中流）对试验场的总产流量也有较大贡献。在径流试验场原型观测基础上,建立了一个基于数字高程模型（DEM）的、包括地表径流、壤中流和基岩裂隙出流的三水源小流域水文模型。利用9次降雨径流过程对模型参数进行率定,利用4次降雨径流过程进行验证,模型的率定、验证均取得了良好的拟合效果。根据模型的模拟结果,在径流的起涨阶段地表产流贡献最大,而基岩裂隙出流对退水过程贡献明显。综合试验场原型观测结果与模型模拟结果得出结论：明显的壤中流和基岩裂隙出流是华南花岗岩小流域显著的产流特点。  相似文献   

13.
Paddy fields are characterized by standing water and saturation condition during the entire crop growth period. However, in sub-humid and semi-arid areas, scarce rainfall and intermittent dry spells often cause soil moisture depletion resulting in unsaturated condition in the fields. These distinctive characteristics of the paddy fields have significant influence on the runoff generation and soil moisture retention characteristics of the watershed. In this study, the objective is to extend the application of the Soil Conservation Services Curve Number (SCS-CN)-based models for the geospatial and temporal simulation of soil moisture to paddy field-dominated agricultural watersheds in the water scarce areas. Different SCS-CN-based models, integrated with the soil moisture balance equation, are used to estimate the surface runoff and soil moisture content wherein, the spatial variation in the soil hydraulic characteristics is used to calculate the geospatial variation in soil moisture content. Physical significance of the terms initial abstraction (Ia) and potential maximum retention (S) in these models and their influence on the estimation of runoff and soil moisture are analysed in detail. A new SCS-CN-based model for soil moisture simulation (SCS-CN-SMS), to improve the soil moisture estimation, is proposed in this paper. The proposed model is built up on the soil moisture balance equation to account for the effect of ponding condition and soil moisture variation between the dry and saturation condition. The method is tested with 3 years observed surface runoff data and crop production statistics from a part of the Gandeshwari sub-watershed in West Bengal, India. The entire study area is divided into cells of 20 m × 20 m. Various components of the soil moisture balance equation are estimated for each cell as a function of the soil moisture content. Remote Sensing Technique and Geographic Information System (GIS) are used to extract and integrate the spatially distributed land use and soil characteristics. The Hortonion overland flow concept adopted in the SCS-CN method is used to estimate the soil hydraulic characteristics of each cell in which the curve number is used to infer the spatial variation of the land use and soil characteristics. Even though the original SCS-CN method and the existing modified versions are efficient for runoff estimation, these models are found to be inappropriate for the estimation of soil moisture distribution. On the other hand, the proposed SCS-CN-SMS model gives better results for both runoff and soil moisture simulation and is, therefore, more suitable for the hydrological modeling of paddy field-dominated agricultural watersheds.  相似文献   

14.
【目的】探索水稻蓄雨间歇灌溉模式节水减排效益。【方法】以鄱阳湖区双季早晚稻为试验材料,采用大田和测坑试验,研究了水稻蓄雨间歇灌溉模式对灌溉定额、排水定额、降雨有效利用率、产量、稻田水分生产率,以及氮、磷排放量的影响,并与间歇灌溉和常规淹水灌溉试验进行了分析比较。【结果】与淹水灌溉、间歇灌溉相比,蓄雨间歇灌溉灌排水量、灌排次数明显减少。双季早晚稻年平均灌水量分别减少975m^3/hm^2和1251m^3/hm^2,年平均灌水次数分别减少8次和7.5次;年平均排水量分别减少729 m^3/hm^2和893 m^3/hm^2,年平均排水次数分别减少5.8次和3.1次;蓄雨间歇灌溉降雨有效利用率明显提高。早稻降雨利用率分别提高12.40%和9.14%,晚稻分别提高6.84%和6.42%;蓄雨间歇灌溉模式下,双季早晚稻总氮排放量年平均减排7.64 kg/hm^2和3.12 kg/hm^2,减排幅度34.93%和14.26%;双季早晚稻总磷排放量0.180kg/hm^2和0.095kg/hm^2,减排幅度37.25%和70.59%。【结论】蓄雨间歇灌溉模式具有明显的节水、减排和提高降雨有效利用率的效果,在我国南方多雨地区具有较强的推广应用空间。  相似文献   

15.
【目的】研究不同灌排模式稻田水氮动态变化,为南方稻作区节水减排提供科学依据。【方法】基于实测的田间灌排水量及氮素变化数据,采用Morris方法检测DRAINMOD模型水氮运移相关参数的灵敏度,并利用DRAINMOD模型对传统灌排模式和控制灌排模式下稻田水氮动态进行模拟。【结果】20~40 cm土层侧向饱和导水率对稻田水分运移模拟结果影响最大,弥散系数、反硝化参数、硝化反应参数、有机质适宜分解温度对稻田氮素运移模拟结果影响较大;DRAINMOD模型能够较好地模拟不同灌排模式稻田水氮动态变化、灌排水量、氮素径流总负荷模拟值与实际值差别小于11%;与传统灌排模式相比,控制灌排模式排水量减少33.0%~72.6%,灌水量减少9.7%~37.1%,铵态氮径流负荷减少43.6%~45.0%,硝态氮径流负荷分别减少29.8%~53.1%。【结论】控制灌排模式稻田节水减排效果较好,利用DRAINMOD模型进行不同灌排模式稻田水氮动态模拟可行有效。  相似文献   

16.
Drainage water quality in rice paddies was strongly influenced by the puddling of soil in the paddy fields by tractors and in response to opening of drainage gates. The concentrations of contaminants in drainage water increased rapidly when the puddling process began and were maintained at high concentrations throughout the puddling period. Moreover, the high concentrations did not decrease immediately after the puddling procedures ceased. Additionally, the ratio of dissolved nitrogen and phosphorous to total nitrogen and total phosphorous increased daily during the last half of the puddling period, due to discharge of chemical fertilizers with the drainage water. Also, the loads of particulate nitrogen and phosphorus discharged during the puddling period were larger than the loads discharge during irrigation. The discharge from paddy fields during puddling also increased the total annual contaminant load.  相似文献   

17.
为探求从化市水南村部分农田被淹没的原因,本文分别采用现场调查、水文地形资料分析、数学模型、调洪演算等方法,对本次流溪河洪水和下游牛心岭电站对淹没位置河段水位的影响进行了分析和探讨。结果表明,洪水从大拗坝到达水南村淹没位置河道的时间约为2.6 h;从5月7日凌晨4点～12点,流溪河水位明显高于淹没区地形,极容易导致外江洪水从未封堵暗渠进入淹没区;牛心岭电站只用4个闸孔泄洪,在洪峰时刻引起淹没区外侧河道水位抬高约0.05 m左右。  相似文献   

18.
河道现状行洪能力是河道所在地区防洪安全的核心,也是防汛主管管部门汛期指导防汛的重要依据。为分析大洋河丹东有堤段的行洪能力,采用水动力模型MIKE11计算、模拟河道及河网的一维洪水演进过程,准确判断其行洪能力,为保护沿岸居民防洪安全提供理论基础。  相似文献   

19.
设计了一个可用于坡面侵蚀过程研究的自动监测径流场,该径流场主要由6个径流小区和1套模拟降雨装置组成。采用德国UGT径流测量装置,实现地表径流的自动采样和记录。用设计的径流场对秸秆覆盖坡耕地的产流产沙过程进行了研究,结果表明相对于裸露地表,秸秆覆盖能明显降低各径流小区的产流率和产沙率,延缓产流增加趋势,减少产沙总量达54.5%~63.8%。因此,增加坡耕地土壤表面的秸秆覆盖量可有效避免产流在短时间内急剧增加,并能减少对土表的冲刷作用。  相似文献   

20.
Micro-catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671 mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158 mm in year 2004/2005, 45 mm in year 2005/2006 and 127 mm in year 2006/2007. About 5000 MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-catchments with catchment areas between 13 and 50 m2 was measured. Also the runoff was indirectly assessed for another 40 micro-catchments by using soil water balance in the micro-catchments and the plant basins. Results show that runoff yield varied between 5 and 187 m3 ha−1 for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%. The rainfall threshold for runoff generation was estimated about 4 mm. Overall; the soil water balance approach predicted 38-57% less water than micro-catchment runoff approach. This difference was due to the reason that the micro-catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning.  相似文献   

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