Rainfall-runoff Analysis Research Articles

나주지점의 강우-유출 해석을 위한 최적의 SOM 구조 결정

인공신경망 이론을 이용하여 강한 비선형성의 경향을 보이고 있는 강우-유출간의 관계를 모형화하기 위한 연구들은 예측뿐만이 아니라 대상자료들의 양상을 분류하여 그 특성을 분석하는 데에도 이용되고 있다. 이와 같은 패턴분류를 위한 SOM(Self-Organizing Map: SOM)의 연구 결과를 검토해보면 SOM 훈련을 위한 지도크기 및 배열의 결정은 SOM 성능에 큰 영향을 미치는 것으로 보고되고 있으나 지도크기 결정시 지도의 종방향 크기와 횡방향 크기를 결정할 수 있는 확정론적인 방법이나 이론식이 없고, 지도배열은 주로 육각형 배열(hexagonal array)을 이용하여 적용하고 있다. 따라서 본 연구에서는 영산강 나주지점을 대상으로 강우-유출관계의 분할특성을 나타내는 지도크기와 배열을 복합적으로 검토하여 나주지점의 강우-유출 해석을 위한 적절한 지도구조를 결정하였다. 그 결과 8개의 패턴으로 구분된 지도크기 20<TEX>$\times$</TEX>16의 육각형배열 구조가 나주지점의 강우-유출해석을 위한 적절한 지도구조로 결정되었다. Studies on modeling the rainfall-runoff relationship which shows nonlinear trend strongly use artificial neural networks theory not only for the prediction but also for the characteristics analysis of the data used by pattern classification. For the pattern classification, the results from Self-Organizing Map (SOM) mention that the map size and array for the SOM training have significantly influenced on the SOM performance. Since there is no deterministic method or theoretical equation to determine the number of rows and columns for the map size, hexagonal array is generally used for the map array. Therefore, this study present a determination of the optimized map structure for the rainfall-runoff analysis in Naju station considering the map size and array simultaneously which can represent the classified characterization of rainfall-runoff relationship. The result showed that the map size of 20<TEX>$\times$</TEX>16 hexagonal array with 8-clustered patterns was selected as an appropriate map structure for rainfall-runoff analysis in Naju station.

Long-term trends of rainfall and runoff regime in upper Otava River basin

The floods experienced recently in the Czech Republic gave rise to numerous discussions over the changed environment and related potential impacts on the rainfall and runoff processes. The main aim of our research project was to determine long term trends of rainfall and runoff regime in Otava River basin. The rainfall-runoff analyses using both the single and double mass curves over the period of the hydrologic observations were taken as a basic method. Beside mean discharge, precipitation, snow and air temperature trends, analysis of land cover change and human impact on the river network and drainage areas development were applied too. The greatest deviations were widely observed in the period between the 2&lt;sup&gt;nd&lt;/sup&gt; half of the seventies and in the 1&lt;sup&gt;st&lt;/sup&gt; half of the eighties. It has been related to the one of repeatedly coming rather humid episodes and correspond to major human influences on the river network. The whole system came slowly back to its initial condition in the early nineties. Standard statistical testing methods were applied to confirm the trends. The Wilcoxon single and paired samples test, and furthermore the Mann-Kendall non-parametric test were used. Trend detection using both tests also confirmed a different development of the discharges and precipitation regime in the Ostružn&amp;aacute; and upper Blanice River basins in the period 1975&amp;ndash;1982. The runoff trend deviation has been related to the nature and human factors, mainly to current climatic changes and changes of landscape retention potential.

Runoff Changes in the Šumava Mountains (Black Forest) and the Foothill Regions: Extent of Influence by Human Impact and Climate Change

The main aim of our research project was to determine the extent to which the outflow can be influenced by human interventions in three selected water basins in the Sumava Mountains (Black Forest) and its foothills. The rainfall-runoff analyses using both the single-mass and double-mass curves over the period of hydrologic observations were taken as a preliminary methodology. Standard statistical testing methods Wilcoxon and Mann–Kendall non-parametric tests were applied to detect the trends. Besides mean discharge, precipitation, snow and air temperature trends, analysis of land cover change and human impact on the river network and development of drainage areas were also carried out. The greatest deviations were widely observed in the period between the second half of the 1970s and the first half of the 1980s. The whole system came slowly back to its initial condition in the early 1990s. The runoff trend deviation was related to natural and human factors, mainly to current climatic changes, river network modification and changes of land cover.

A joint model for rainfall–runoff: The case of Rio Grande Basin

Summary We present an analysis of runoff and rainfall data from Rio Grande, a basin located in the northeast of Brazil. The main challenges we face here are: (i) to model runoff and rainfall jointly, taking into account their different spatial units, (ii) to use stochastic models where all the parameters have physical interpretations, and (iii) to model these processes in their original scale, without assuming any transformation to attain normality of these variables. The intrinsically uncertain nature of these hydrological processes makes Bayesian analysis natural in this field. Our approach is based on dynamic models. The effect of rainfall on runoff is modeled through a transfer function, whereas the amount of rainfall is obtained after fitting a spatio-temporal model and dealing with the change of support problem. Besides the computational effort to implement the proposed models, some methodological novelties are also implemented. The data consist of monthly series from January 1984 to September 2004, at a runoff station and nine rainfall stations irregularly located in a drainage area of 37522.48 km2. Model assessment, spatial interpolation and temporal predictions were part of our analysis. The results show that our approach is a promising tool for rainfall–runoff analysis.

Estimation of field irrigation water demand based on lumped kinematic wave model considering soil moisture balance

An estimation model of farm field irrigation water demand is developed. The model is based on the lumped kinematic wave model considering soil water balance. The lumped model approach reduces the computational load in rainfall–runoff analysis and allows application to large river basins. Evapotranspiration is estimated on hourly basis by the improvement of FAO’s method. Not only water volume necessary for farm field irrigation but also the number of the water charge and its interval can be estimated by the combined use of the lumped runoff model and the hourly evapotranspiration model.

Prediction versus Understanding (The 2006 Ven Te Chow Lecture)

flow hydrographs and peak flows on the time scales of individual rainfall-runoff events. This in contrast to the statistical approach, which was spatial. The two approaches were developed to solve practical engineering problems. The regional statistical analysis of annual flood frequencies was designed to predict floods of a given return period for highway, bridge, and spillway design at ungauged locations, and rainfall-runoff models were developed for planning and project design. The dichotomy in the two approaches to hydrologic analyses continues until today in hydrologic research, education, and practice. It was also recognized in the early 1960s that the two approaches must be closely connected because physical rainfallrunoff mechanisms generating floods were the basis for the flood values used in the statistical analysis. For example, federal agencies other than the USGS have often used deterministic rainfallrunoff analyses to determine flood frequencies. An intercomparison of use of the various models for the prediction of flood frequencies was undertaken, and it was shown that the USGS model predicted with less bias and less variance than any of the other models. Thus, once again, better understanding did not lead to better prediction. However, a general theoretical framework for connecting the two, i.e., how the physics of the system could be used to predict spatial statistical parameters in quantile analysis was not known, and tools had not been developed to address this fundamental hydrologic question. The parameters used in the regression models were surrogates for the physics underpinning the prediction. However, it was not recognized at the time that the problem of connecting the two approaches was a nonlinear geophysical problem belonging to hydrological sciences rather than a practical engineering problem belonging to hydrologic engineering and that it required the development of new ideas and new tools.

복수의 임펄스 응답을 이용한 강우-유출 해석

최근들어 강우-유출 현상에 관한 비선형 모델링에 관하여 많은 연구가 있어 왔는데, 그 중에서도 신경망을 이용한 결과는 매우 성공적인 것으로 보고되어 왔다. 선형 구조가 갖는 근본적인 한계성으로 인하여, 이 분야에 선형 모델을 활용하는 것은 신경망을 사용하는 경우에 비하여 불리할 것으로 여겨지곤 한다. 하지만 우리는, 선형 모델의 경우 주어진 문제가 갖는 근본적 동특성의 원리를 보다 잘 이해할 수 있도록 해주므로, 적절한 확장 과정을 거치면 선형 임펄스 응답의 개념은 매우 경쟁력 있는 도구가 될 수 있을 것으로 생각한다. 이러한 생각에 따라, 본 논문에서 우리는 복수의 임펄스 응답의 이용을 강우-유출 해석의 문제에 적용하는 방안을 제안한다. 제안된 방법은 복수의 임펄스 응답 모델 사이에 적용되는 단순하고 고정된 스위칭 전략에 기반을 두고 있으며, 각 임펄스 응답은 음이 아닌 성분을 갖도록 하고, 동시에 한개의 봉우리만 갖는 형태를 만족하도록 한다. 우리나라의 특정한 지역의 수문기상학 자료를 대상으로 하여 적용해 본 결과, 제안된 방법은 매우 의미 있는 결과를 제공함을 보여주었다. There have been many recent studies on the nonlinear rainfall-runoff modeling, where the use of neural networks is shown to be quite successful. Due to fundamental limitation of linear structures, employing linear models has often been considered inferior to the neural network approaches in this area. However, we believe that with an appropriate extension, the concept of linear impulse responses can be a viable tool since it enables us to understand underlying dynamics principles better. In this paper, we propose the use of multiple impulse responses for the problem of rainfall-runoff analysis. The proposed method is based on a simple and fixed strategy for switching among multiple linear impulse-response models, each of which satisfies the constraints of non-negativity and uni-modality. The computational analysis performed for a certain Korean hydrometeorologic data set showed that the proposed method can yield very meaningful results.

Enhancing multi-functionality of agriculture through rainwater harvesting system

The multi-functionality of agriculture was studied from June to December 2005 in an upland community in Central Luzon, Philippines, by looking across the entire basin of two small water impounding systems or SWIP (Maasin and Buted II). Several sub-studies were undertaken, namely (a) the role of dominant vegetative cover on the rate of surface runoff and erosion; (b) rainfall–runoff analysis in a sub-watershed (i.e., through runoff experimental plot) and within the main watershed (i.e., reservoir inflow analysis); and (c) the environmental functions of agriculture across the entire watershed. The results indicated that about 85% (i.e., throughfall) of rainfall could reach the ground as vegetations intercept the rest. The runoff experimental plot covering a sub-watershed revealed a good correlation between throughfall and runoff. On the other hand, monitoring of reservoir inflows through which surface runoff was measured indicated similar behavior. Integrating the result of runoff experimental plot studies and reservoir inflow analysis resulted to a rainfall–runoff relation which can be applied in the development of rainwater harvesting scheme. The result also showed the dominance of surface runoff as the main component of reservoir inflow, confirming the soil and water conservation, and flood prevention functions of the system. Flood analysis conducted in both SWIP confirmed their flood prevention function by reducing flood peak discharge. The difference between with and without the reservoir was also highlighted in the process. In the paddy field, a 5-cm water depth was consistently maintained, contributing in retaining about 0.543 and 0.272 MCM of rainwater in Maasin and Buted II, respectively. The value of fostering groundwater recharge throughout the entire system was almost equivalent to the value of flood prevention function. Moreover, SWIP also trapped sediments, thereby preventing offsite impact downstream and in surrounding areas.

Runoff changes according to human impact on the landscape

The main aim of our research project was to determine the extent to which the outflow can be influenced by the human interventions in three-selected water basins in Bohemian Forest (Šumava Mountains) and foothills. The rainfall-runoff analyses using both the single and double mass curves over the period of the hydrologic observations were taken as a basic methodology. Beside mean discharge, precipitation, snow and air temperature trends, analysis of land cover change and human impact on the river network and drainage areas development were applied too. The greatest deviations were widely observed in the period between the 2nd half of the seventies and in the 1st half of the eighties. The whole system came slowly back to its initial condition in the early nineties. The runoff trend deviation has been related to the nature and human factors, mainly to current climatic changes and changes of landscape retention potential.

SCS 방법 적용을 위한 선행토양함수조건의 재설정: 1. SCS 방법 검토 및 적용상 문제점

선행함수조건(AMC)에 따라 유출용적이 매우 다르게 나타날 수 있음에도 불구하고 우리나라에서의 강우-유출 해석에는 그 적용성에 대한 평가 없이 미국에서 개발된 AMC조건(SCS, 1972)이 일반적으로 그대로 이용되고 있다. 본 연구에서는 SCS의 CN 결정과정을 그대로 따라 평창강 유역의 장평 소유역에 대해 CN 값을 추정하고 이를 이용하여 AMC 조건을 평가하였다. 그 결과 CN(I), CN(II), CN(III)가 각각 72.1, 79.3, 76.7로 추정되었다. CN(II)의 경우는 기존 보고서와 유사한 값을 보여주고 있으나 나머지 값의 경우는 이론적인 값과 매우 동떨어진 결과를 나타내고 있다. 그러나 CN의 평가만으로 AMC 조건의 적절성을 판단하는 것은 어려우며, 오히려 AMC 조건의 발생 빈도를 검토하여 AMC 조건의 적절성은 판단하는 것이 바람직하다. 본 연구에서도 AMC 조건별로 호우사상의 발생빈도를 히스토그램으로 작성/비교하였으며, AMC-III 조건은 상향될 필요가, 반대로 AMC-I 조건은 하향될 필요가 있음을 확인하였다. Even though the runoff volume is very sensitive to the antecedent soil moisture condition (AMC), the general rainfall-runoff analysis in Korea has accepted, without careful consideration of its applicability, the AMC classification of the Soil Conservation Service (SCS, 1972). In this study, by following the development procedure of SCS Curve Number (CN), the rainfall-runoff characteristics of the Jangpyung subbasin of the Pyungchang River Basin were analyzed to estimate the CN and evaluate the AMC classification of currently being used. As results, CN(I), CN(II), and CN(III) were estimated to be 72.1, 79.3, and 76.7, respectively. Among them CN(II) was found to be similar to the other reports but the other two were totally different from those of theoretically estimated. However, it is difficult to evaluate the AMC with CN, rather the frequency of each AMC could be a better indicator for its validity. This study developed the histogram of AMC and compared the frequency of each AMC. hs results we found that the criterion for AMC-III should be increased, Hut that for AMC-I decreased.

Freshwater discharge from the drainage basin to the Venice Lagoon (Italy)

The twelve major tributaries of the Venice Lagoon (accounting for the 97% of the inputs from the drainage basin) were monitored in the framework of the DRAIN project (1998–2000) in order to obtain a detailed knowledge on the hydrological regimes and to measure the mean annual freshwater discharge from surface runoff. The study represents an essential step in the estimate of the pollutant load delivered to the lagoon that must necessarily be based on a solid understanding of the fluxes of material out of the drainage basin. Due to the influence of the tide in the majority of the gauging sections, a specific methodology for the measurement of the discharge was developed. The main results of the study are described, underlining the differences in the regime of the investigated streams. A rainfall–runoff analysis evidenced the different characteristics of the monitored tributaries, in terms of specific hydrological features, morphology of the individual sub-basins, management of the water resource and spatial distribution of rainfall. An estimate of the maximum peak discharge from the drainage basin is finally obtained from data of an extreme flood event occurred in November 1999.

지표홍수 빈도곡선의 개발에 의한 미 계측지점의 확률 홍수량 추정

본 연구에서는 지표홍수 빈도곡선을 개발하여 미계측 지점에서의 확률 홍수량을 추정해 보았다. 홍수빈도 분석은 한강유역의 9개 지점에 대하여 연최대치 홍수량 자료를 이용하여 분석하였다. 홍수빈도 곡선을 작성한 후 각 지점별 연평균홍수량( <TEX>$Q_{2.33}$</TEX>)을 결정하였고, 각 지점별 재현기간에 따른 연평균 홍수량에 대한 비를 산정 후 평균하였다. 그 결과 재현기간별로 다른 홍수량비가 산정되었다. 연평균 홍수량과 유역의 지형인자와의 상관 분석을 통해 다중선형 회귀식을 도출하였다. 미계측 지점의 확률 홍수량은 그 지점의 유역면적과 하상경사를 이용하여 경험식에 의해 연평균 홍수량을 산정 한 후 재현기간에 따른 홍수량비를 곱하여 산정 할 수 있다. 본 연구의 검증을 위하여 하천정비 기본계획에 수록되어 있는 재현기간별 확률홍수량과 비교한 결과 유역면적 2,000k <TEX>$m^2$</TEX> 이하의 유역에서는 유사한 값을 모의 할 수 있었다. 기존 강우-유출 해석을 기반으로 한 설계 홍수량 추정 방법에의 적용은 재평가되어야 한다. 왜냐하면, 수문자료와 강우-유출모형은 많은 불확실성이 내포하고 있기 때문이다. The study shows the possible use of the index flood frequency curves for an estimation of flood quantiles at ungauged locations. Flood frequency analysis were made for the annual maximum flood data series at 9 available stations in the Han river basin. From the flood frquency curve at each station the mean annual flood of 2.33-year return period was determined and the ratios of the flood magnitude of various return period to the mean annual flood at each station were averaged throughout the Han river basin, resulting mean flood ratios of different return periods. A correlation analysis was made between the mean annual flood and physiographic parameters of the watersheds i.e, the watershed area and mean river channel slope, resulting an empirical multiple linear regression equation over the whole Han river basin. For unguaged watershed the flood of a specified return period could be estimated by multiplying the mead flood ratio corresponding the return period with the mean annual flood computed by the empirical formula developed in terms of the watershed area and river channel slope. To verify the applicability of the methodology developed in the present study the floods of various return periods determined for the watershed in the river channel improvement plan formulation by the Ministry of Construction and Transportation(MOCT) were compared with those estimated by the present method. The result proved a resonable agreement up to the watershed area of approximately 2,000k <TEX>$m^2$</TEX>. It is suggested that the practice of design flood estimation based on the rainfall-runoff analysis might have to be reevaluated because it involves too much uncertainties in the hydrologic data and rainfall-runoff model calibration.

Diffusive tank model application in rainfall-runoff analysis of upland fields in Taiwan

Drainage analyses were performed on catchments with a mixture of paddy and upland fields. In this study, the simulations adopt the diffusive tank model concept, which has been applied successfully for rainfall-runoff analyses in paddy fields. Considering the drainage characteristic discrepancy between the paddy and upland fields, a new outflow formula with corresponding model parameters based on a weir formula was proposed to reflect the flow behavior from the outlet of the upland fields. To evaluate the applicability of the proposed model, field measurements were carried out at two experimental catchments and the results were used to calibrate the model parameters and for verifications. Results show that the measured and simulated data are in a good agreement, indicating that the proposed model is applicable for rainfall-runoff analyses in local areas mixed with paddy and upland fields.

GIS와 불확실도 해석기법을 이용한 분포형 강우 -유출 모형의 개발 (II) - 적용 및 분석 -

In this study(II), the model developed in the previous study(I) has been tested on two cases of constant-slope areas to verify the model applicability. Firstly, an impervious one-dimensional runoff problem has been simulated. Secondly, an impervious two-dimensional runoff problem at a converging plain which consists of a V-shaped section plus a portion of the surface of a cone has been simulated. For each case, the simulation results have good agreements with the observed data. And the model has been applied to actual watersheds, which were the Sulma watershed with 8 and the Donggok watershed with 33.2, drainage area, respectively. The simulated results agree with observed in terms of discharges at several stations. Monte Carlo simulation was also performed on the same watersheds and the modeling results have been evaluated. The suggested model can be used for real-time forecasting of rainfall-runoff analysis, and will contribute for basinwide flood control in the future.

土地利用別メッシュタンクモデルを用いた湿原流域降雨流出解析

本研究では，北海道道東に位置する別寒辺牛湿原流域を対象にして，土地利用別メッシュタンクモデルを用いて湿原の降雨流出特性を把握することを目的とした．土地利用別のタンクの構造を決定するために，流域内の優占土地利用が異なる8ポイントで流量観測をおこなった．実測値との比較により構築されたモデルでは，従来から把握されていた牧草地や森林の流出特性に加えて，湿原の降雨流出特性も把握することができた．湿原を含む流域では，湿原メッシュのタンク構造を水深により変動させた．また，河川の周辺が湿原である場合は，河川からのオーバーフロー現象を取り入れた．

지형공간 특성자료를 이용한 하천유역의 강우-유출해석

지형공간 특성자료를 이용한 하천유역의 강우-유출해석

하천유역에서 GIS를 이용한 GIUH 모형의 해석

본 연구는 미 계측유역이나 자료가 결핍된 유역에서 지리정보시스템을 이용하여 지형학적 순간단위도(GIS-GIUH)를 해석하는데 목적이 있으며, IHP 위천대표시험유역의 6개지점(동곡, 고로, 미성, 병천, 효령, 무성)에 대하여 강우-유출해석을 실시하였다. 지형학적 순간단위도의 분석에는 본 연구에서 제안한 GIS-GIUH 모형과 Rosso-GIUH 모형을 이용하여 계산된 결과를 실측유출수문곡선과 비교하였다. 분석결과 GIS-GIUH 모형이 Rosso-GIUH 모형보다 실측수문곡선에 더욱 접근하여 우수한 결과를 보이고 있었으며, GIS-GIUH 모형의 매개변수인 N=3.25( <TEX>$R_{B}$</TEX>/ <TEX>$R_{A}$</TEX>)<TEX>$^{0.126}$</TEX> <TEX>$R_{L}$</TEX><TEX>$^{-0.055}$</TEX>과 K=1.50( <TEX>$R_{A}$</TEX>/( <TEX>$R_{B}$</TEX>. <TEX>$R_{L}$</TEX>))/<TEX>$^{0.10}$</TEX>.(( <TEX>$L_{{\Omega}}$</TEX>+ <TEX>$L_{{\Omega}-1}$</TEX>)/V)<TEX>$^{0.37}$</TEX>을 지형특성의 관계식으로 제시하였다. 본 연구에서 개발한 GIS-GIUH 모형이 미계측 유역에서 적용 가능성이 높은 것으로 판단되었다.되었다. This study aims at the analysis of the geomorphological instantaneous unit hydrograph model (GIS-GIUH) with geographic information system for the rainfall-runoff analysis of watershed which is ungaged or doesn't have sufficient hydrologic data. The rainfall-runoff analysis was performed in Wi stream(Dongkok, Koro, Miseung, Byeungchun, Hyoreung, Museung) which is a representative experimental river basin of IHP. In the process of analysis of the GIUH model, developed GIS-GIUH model and Rosso-GIUH model were applied the study basin and computed hydrographs by these models were compared with observed hydrograph. The GiS-GIUH model shows more closely to the observed hydrograph than Rosso-GIUH model in the peak discharge of the hydrograph. For the development of the GIS-GIUH model, Gamma function factor N was given by N=3.25( <TEX>$R_{B}$</TEX>/ <TEX>$R_{A}$</TEX>)<TEX>$^{0.126}$</TEX> <TEX>$R_{L}$</TEX><TEX>$^{-0.055}$</TEX>, which is the relation of the watershed geomorphological factor, K was also obtained as K=1.50( <TEX>$R_{A}$</TEX>/( <TEX>$R_{B}$</TEX>. <TEX>$R_{L}$</TEX>))/<TEX>$^{0.10}$</TEX>.(( <TEX>$L_{{\Omega}}$</TEX>+ <TEX>$L_{{\Omega}-1}$</TEX>)/V)<TEX>$^{0.37}$</TEX>. As the results of analysis, it was found that GIS-GIUH model can be applied to an ungaged watersheds.eds.

Development of a fuzzy logic-based rainfall-runoff model

Rainfall-runoff models are used to describe the hydrological behaviour of a river catchment. Many different models exist to simulate the physical processes of the relationship between precipitation and runoff. Some of them are based on simple and easy-to-handle concepts, others on highly sophisticated physical and mathematical approaches that require extreme effort in data input and handling. Recently, mathematical methods using linguistic variables, rather than conventional numerical variables applied extensively in other disciplines, are encroaching in hydrological studies. Among these is the application of a fuzzy rule-based modelling. In this paper an attempt was made to develop fuzzy rule-based routines to simulate the different processes involved in the generation of runoff from precipitation. These routines were implemented within a conceptual, modular, and semi-distributed model-the HBV model. The investigation involved determining which modules of this model could be replaced by the new approach and the necessary input data were identified. A fuzzy rule-based routine was then developed for each of the modules selected, and application and validation of the model was done on a rainfall-runoff analysis of the Neckar River catchment, in southwest Germany.

Unit Hydrograph Derivation for Ungauged Watersheds by Stream-Order Laws

Hydrologists have attempted to relate the hydrologic response of watersheds as runoff production from rainfall to watershed topographic structures for many years. The recently proposed geomorphologic instantaneous unit hydrograph (GIUH) method is perhaps the most promising development in this direction; if successful, it would allow the derivation of the unit hydrograph (UH) for ungaged or inadequately gaged watersheds without the need of observed runoff and rainfall data. In this method, the geomorphic ratios of the Horton-Strahler stream-ordering laws are incorporated in the GIUH model for UH generation. In view of the variety of project requirements and the different levels of topographic detail available from maps or geographic information systems (GISs) five different levels of geomorphic data are allowed for incorporation with a kinematic-wave and stream-law based instantaneous UH model. Testing of the model on two hilly watersheds in the eastern United States and two relatively flat-slope watersheds in Illinois are presented. Comparison between the simulated and observed hydrographs for a number of rainstorms indicate the potential of this model as a useful tool in watershed rainfall-runoff analysis.

Management of runoff stored in small tanks for transplanted rice production in the mid-hills of Northwest Himalaya

Scarcity of water in upland areas limits the growing of transplanted rice and the yield of rice grown under rainfed conditions is very low. As the first priority for the use of runoff recycling based water resources is in the dry season followed by the monsoon season, a strategy has been developed to use the surplus water (occurring during the early monsoon season) to grow transplanted rice without compromising the dry season irrigation. Field experiments revealed that under the mid-hill conditions, transplanted rice can be grown as transplanted in 5 cm standing water and thereafter tainted, requiring only 3.0–3.5 cm of water with a yield reduction of about 25% as compared to generally recommended intermittent submergence (2 days after the disappearance of water) requiring 100–130 cm of water. However, the reduction in yield was not significant if 1 week of initial ponding just after transplanting was created. Based on rainfall-runoff analysis, graphs were developed for runoff and volume of water available in water tanks in different durations of early monsoon periods, command-catchment area ratio and the volume of water available after irrigation which is to be used in dry season, as a function of runoff curve numbers. These graphs can be consulted directly to plan irrigation systems for transplanted rice in upland areas.