Sudhindra N. Panda

Field test of a soil water balance simulation model

A simple soil water balance model is used to simulate the soil water content in the active root zone of mustard crop (Brassica juncea) as well as is tested with field experimental data of 2 years (1998 and 1999) under rain-fed (no irrigation) and irrigated conditions. The model used includes physical process like infiltration from rainfall or irrigation, redistribution in soil water zone, plant water uptake in the form of actual evapotranspiration and percolation out of the soil reservoir. In addition, the model considers dynamics of crop root growth model that affect the plant water uptake and hence the soil water in the unsaturated zone. The model satisfactorily simulates the soil water content in the active root zone of the crop on daily basis. Values of the mean absolute relative error (MARE) index between the observed and simulated soil water content of the rain-fed mustard in 1998 and 1999 are found to be 0.046 and 0.058, respectively, whereas for irrigated mustard, it is 0.051 in 1999. Prediction efficiency (PE) index is found to be 0.98, 0.97 and 0.97 for rain-fed mustard of 1998 and 1999 and irrigated mustard of 1999, respectively. Since the MARE index is low and PE index is high for both rain-fed and irrigated mustard, the model can be used to simulate the soil water content in the active root zone of the crop.

Optimal crop planning and conjunctive use of water resources in a coastal river basin

Due to increasing trend of intensive rice cultivation in a coastal river basin, crop planning and groundwater management areimperative for the sustainable agriculture. For effective management, two models have been developed viz. groundwater balance model and optimum cropping and groundwater management model to determine optimum cropping pattern and groundwater allocation from private and government tubewells according to different soil types (saline and non-saline), type of agriculture(rainfed and irrigated) and seasons (monsoon and winter). A groundwater balance model has been developed considering mass balance approach. The components of the groundwater balance considered are recharge from rainfall, irrigated rice and non-rice fields, base flow from rivers and seepage flow from surface drains. In the second phase, a linear programming optimization model is developed for optimal cropping and groundwater management for maximizing the economic returns. Themodels developed were applied to a portion of coastal river basin in Orissa State, India and optimal cropping pattern forvarious scenarios of river flow and groundwater availability wasobtained.

EFFECT OF SALINE IRRIGATION WATER ON MUSTARD ( BRASSICA JUNCEA ) CROP YIELD AND SOIL SALINITY IN A SEMI-ARID AREA OF NORTH INDIA

The groundwater in some parts of north India is generally saline and not suitable for drinking. However, it can be used for growing salt-tolerant crop plants. To explore the potential of using saline groundwater for farm production, a field experiment was conducted at Shahpur village, near Hisar in Haryana State, India, to study the effect of different qualities of irrigation water on mustard (Brassica juncea, cv. RH–30) crop growth, yield, water use efficiency and soil salinity. Treatments consisted of combinations of irrigation with saline groundwater (electrical conductivity (EC) 7.48 dS m−1), and a good quality canal water (EC 0.4 dS m−1) applied either alone, as blends or in alternate applications. In all treatments, canal water was used for pre-sowing irrigation. In mustard cultivation, saline groundwater with an EC of 7.48 dS m−1 can be used safely to supplement all post-sowing irrigations with marginal decline in crop yield. Irrigation with saline groundwater gave a yield as high as 95% of the optimum crop yield obtained with fresh canal water. The temporal variation in salinity showed that mustard yield responds to the average salinity of the soil during the growing season. Thus saline groundwater is a good water source to exploit for supplemental irrigation.

A sediment graph model based on SCS-CN method

Sediment is fragmented material primarily formed by the physical and chemical disintegration of rocks from the earths crust. For example, physical disintegration means where the material is broken down by human interference or can be due to the construction or engineering works. Similarly chemical disintegration is by chemicals in fluids, wind, water or ice and/or by the force of gravity acting on the particle itself. The estimation of sediment yield is needed for studies of reservoir sedimentation, river morphology and soil and water conservation planning. However, sediment yield estimate of a watershed is difficult as it results due to a complex interaction between topographical, geological and soil characteristics. In spite of extensive studies on the erosion process and sediment transport modelling, there exists a lack of universally accepted sediment yield formulae (Bhunya et al. 2010). The conditions that will transport sediment are needed for engineering problems, for example, during canal construction, channel maintenance etc. Interpreting ancient sediments; most sediments are laid down under processes associated with flowing water like rivers, ocean currents and tides. Usually, the transport of particles by rolling, sliding and saltating is called bed-load transport, while the suspended particles are transported as suspended load transport. The suspended load may also include the fine silt particles brought into suspension from the catchment area rather than from, the streambed material (bed material load) and is called the wash load. An important characteristic of wash load is that its concentration is approximately uniform for all points of the cross-section of a river. This implies that only a single point measurement is sufficient to determine the cross-section integrated wash-load transport by multiplying with discharge. In estuaries clay and silt concentrations are generally not uniformly distributed. Bed load refers to the sediment which is in almost continuous contact with the bed, carried forward by rolling, sliding or hopping. Suspended load refers to that part of the total sediment transport which is maintained in suspension by turbulence in the flowing water for considerable periods of time without contact with the stream bed. It moves with practically

Integrated Salt and Water Balance Modeling for the Management of Waterlogging and Salinization. I: Validation of SAHYSMOD

Irrigated agriculture faces serious threats of waterlogging and soil salinization in the arid and semiarid regions of the world. In this paper, an integrated spatial-agro-hydro-salinity model (SAHYSMOD) was used to analyze water and salt balances of an irrigated semiarid area located in the Haryana State of India where the groundwater level is rising continuously. The calibration, validation, error analysis, and sensitivity analysis of the model parameters were performed. The sensitivity analysis revealed that hydraulic conductivity is the most sensitive model parameter for both groundwater levels and salinities, followed by effective porosity of the aquifer. The leaching efficiency of the soil is sensitive only to the groundwater salinities. The results show a good agreement between the simulated and observed groundwater levels and salinities for almost all the nodes during the calibration and validation periods. The results are also substantiated by the high R-squared values and low mean error (ME) and root mean square error (RMSE) values. On the basis of the results, it could be concluded that the SAHYSMOD performed very well in predicting groundwater levels and salinities during the calibration and validation periods.

Simulation of water harvesting potential in rainfed ricelands using water balance model

Abstract Using daily water balance simulation in rainfed ricelands, the study estimates the probable supplemental irrigation (SI) requirement to meet the water deficits during the reproductive stage of rice and surface runoff (SR) generated that can be harvested in OFR for meeting the aforesaid SI. Value of SI of rice during reproductive stage at 25% probability of exceedence (PE) was found to be 144 mm, neglecting distribution and application losses. Water harvesting potential of the study area indicates that at 50% PE, 85% of SI of rice can be met from the SR generated from the ricelands and stored in OFR. Rest amount of SI can be met from the direct conservation of rainfall in a lined OFR of 2 m depth with 1:1 side slope occupying 9% ricelands. Economic analysis of OFR irrigation system reveals that OFR of 9% ricelands gives net profit (NP) of Indian Rupees (Rs.) 13445 (US

Synthetic Unit Hydrograph Methods: A Critical Review

295.49) for 1 ha sown with dry seeded rainfed upland rice with benefit–cost ratio (BCR) of 1.25. Values of NP and BCR indicate that investment in OFR irrigation system is profitable in the study region.

Optimization Modeling for Conjunctive Use Planning of Surface Water and Groundwater for Irrigation

The present study critically reviews the synthetic unit hydrograph (SUH) methods available in hydrologic lit- erature. The study reveals that the traditional methods of SUH derivation, e.g., Snyder, SCS, traditional methods like Sny- der and TS method that does not yield satisfactory results, and their application to the practical engineering problems is tedious and combursome. On the other hand, probability distribution functions (pdfs) based SUH methods are easy to ap- ply, and easily meet the UH criterion, i.e. the area under the curve is unity, and rely on a stronger mathematical base and sounder hydrologic perception. The recent pdfs used for deriving UHs in ungauged catchments, address the SUH shapes with more flexibility than the earlier pdfs proposed by (1) for SUH derivation.

Drought Impacts and Adaptation Strategies for Agriculture and Rural Livelihood in the Maharashtra State of India

AbstractThe continuous increase in global population and simultaneous decrease in good-quality water resources emphasize the need of conjunctive use of groundwater and surface-water resources for irrigation. The optimal allocation of water resources can be achieved by employing an appropriate optimization technique. This paper presents an overview of the different programming techniques used for the conjunctive use planning and management of irrigated agriculture. Past papers on the applications of different programming techniques for the conjunctive use of different water sources are grouped into four categories: linear programming, nonlinear programming, dynamic programming, and genetic algorithms. Conclusions are provided based on this review, which could be useful for all stakeholders.

Ecologically sustainable surface water withdrawal for cropland irrigation through incorporation of climate variability

Nearly one-sixth of India is defined as a Drought Prone Area, and as such recurring drought is one of the major challenges in the region. This article focuses on various drought impacts in an important state of India (i.e. Maharashtra State), which contributes about 15% of the country’s gross domestic product (GDP). Drought impacts vary from region to region, but the overall issues are similar and Maharashtra State is indicative of the rest of the Drought Prone Area of the country. This article briefly reviews the major impacts of the 2012 drought on Maharashtra State’s water resources, agriculture, food security, adopted adaptation and mitigation measures and also outlines scope for future research.