Improved Algorithms for Reservoir Capacity Calculation Incorporating Storage-Dependent Losses and Reliability Norm

Two algorithms that improve upon the sequent-peak procedure for reservoir capacity calculation are presented. The first incorporates storage-dependent losses (like evaporation losses) exactly as the standard linear programming formulation does. The second extends the first so as to enable designing with less than maximum reliability even when allowable shortfall in any failure year is also specified. Together, the algorithms provide a more accurate, flexible and yet fast method of calculating the storage capacity requirement in preliminary screening and optimization models.

Locus Bonus : The Relationship of the Roman Villa to its Environment in the Vicinity of Rome

The aim of this study is to examine the relationship of the Roman villa to its environment. The villa was an important feature of the countryside intended both for agricultural production and for leisure. Manuals of Roman agriculture give instructions on how to select a location for an estate. The ideal location was a moderate slope facing east or south in a healthy area and good neighborhood, near good water resources and fertile soils. A road or a navigable river or the sea was needed for transportation of produce. A market for selling the produce, a town or a village, should have been nearby. The research area is the surroundings of the city of Rome, a key area for the development of the villa. The materials used consist of archaeological settlement sites, literary and epigraphical evidence as well as environmental data. The sites include all settlement sites from the 7th century BC to 5th century AD to examine changes in the tradition of site selection. Geographical Information Systems were used to analyze the data. Six aspects of location were examined: geology, soils, water resources, terrain, visibility/viewability and relationship to roads and habitation centers. Geology was important for finding building materials and the large villas from the 2nd century BC onwards are close to sources of building stones. Fertile soils were sought even in the period of the densest settlement. The area is rich in water, both rainfall and groundwater, and finding a water supply was fairly easy. A certain kind of terrain was sought over very long periods: a small spur or ridge shoulder facing preferably south with an open area in front of the site. The most popular villa resorts are located on the slopes visible from almost the entire Roman region. A visible villa served the social and political aspirations of the owner, whereas being in the villa created a sense of privacy. The area has a very dense road network ensuring good connectivity from almost anywhere in the region. The best visibility/viewability, dense settlement and most burials by roads coincide, creating a good neighborhood. The locations featuring the most qualities cover nearly a quarter of the area and more than half of the settlement sites are located in them. The ideal location was based on centuries of practical experience and rationalized by the literary tradition.

How effective are broad-scale nutrient mass balances for determining the sustainability of lot-feed manure application?

Nutrient mass balances have been used to assess a variety of land resource scenarios, at various scales. They are widely used as a simple basis for policy, planning, and regulatory decisions but it is not clear how accurately they reflect reality. This study provides a critique of broad-scale nutrient mass balances, with particular application to the fertiliser use of beef lot-feeding manure in Queensland. Mass balances completed at the district and farm scale were found to misrepresent actual manure management behaviour and potentially the risk of nutrient contamination of water resources. The difficulties of handling stockpile manure and concerns about soil compaction mean that manure is spread thickly over a few paddocks at a time and not evenly across a whole farm. Consequently, higher nutrient loads were applied to a single paddock less frequently than annually. This resulted in years with excess nitrogen, phosphorus, and potassium remaining in the soil profile. This conclusion was supported by evidence of significant nutrient movement in several of the soil profiles studied. Spreading manure is profitable, but maximum returns can be associated with increased risk of nutrient leaching relative to conventional inorganic fertiliser practices. Bio-economic simulations found this increased risk where manure was applied to supply crop nitrogen requirements (the practice of the case study farms, 200-5000 head lot-feeders). Thus, the use of broad-scale mass balances can be misleading because paddock management is spatially heterogeneous and this leads to increased local potential for nutrient loss. In response to the effect of spatial heterogeneity policy makers who intend to use mass balance techniques to estimate potential for nutrient contamination should apply these techniques conservatively.

Flow impacts on estuarine finfish fisheries of the Gulf of Carpentaria

The estuaries of Australia s tropical rivers support commercial fisheries for finfish and shellfish valued at over $220 million per annum. There are also significant tourism-related and local recreational and indigenous fisheries for icon species such as barramundi. Development of water resources in Australia's Tropical Rivers region is being considered for the Flinders, Mitchell, McArthur, Roper, Daly and Victoria catchments. Greater knowledge of the freshwater requirements of tropical aquatic ecosystems, including estuaries is crucial, so that the communities of catchments where water resource development occurs can be assured that the downstream effects of such development are considered and managed based on the best available knowledge.

Multiobjective Analysis of Irrigation Planning in River Basin Development

A river basin that is extensively developed in the downstream reaches and that has a high potential for development in the upper reaches is considered for irrigation planning. A four-reservoir system is modeled on a monthly basis by using a mathematical programing (LP) formulation to find optimum cropping patterns, subject to land, water, and downstream release constraints. The model is applied to a fiver basin in India. Two objectives, maximizing net economic benefits and maximizing irrigated cropped area, considered in the model are analyzed in the context of multiobjective planning, and the tradeoffs are discussed.

Complementary forages – integration at a whole-farm level

A high proportion of the Australian and New Zealand dairy industry is based on a relatively simple, low input and low cost pasture feedbase. These factors enable this type of production system to remain internationally competitive. However, a key limitation of pasture-based dairy systems is periodic imbalances between herd intake requirements and pasture DM production, caused by strong seasonality and high inter-annual variation in feed supply. This disparity can be moderated to a certain degree through the strategic management of the herd through altering calving dates and stocking rates, and the feedbase by conserving excess forage and irrigating to flatten seasonal forage availability. Australasian dairy systems are experiencing emerging market and environmental challenges, which includes increased competition for land and water resources, decreasing terms of trade, a changing and variable climate, an increasing environmental focus that requires improved nutrient and water-use efficiency and lower greenhouse gas emissions. The integration of complementary forages has long been viewed as a means to manipulate the home-grown feed supply, to improve the nutritive value and DM intake of the diet, and to increase the efficiency of inputs utilised. Only recently has integrating complementary forages at the whole-farm system level received the significant attention and investment required to examine their potential benefit. Recent whole-of-farm research undertaken in both Australia and New Zealand has highlighted the importance of understanding the challenges of the current feedbase and the level of complementarity between forage types required to improve profit, manage risk and/or alleviate/mitigate against adverse outcomes. This paper reviews the most recent systems-level research into complementary forages, discusses approaches to modelling their integration at the whole-farm level and highlights the potential of complementary forages to address the major challenges currently facing pasture-based dairy systems.

Interface between 2 dissimilar fluids beneath a sheetpile cofferdam

A closed form solution is presented for determining the shape and location of the interface between two dissimilar fluids (having different densities) when steady flow takes place through a homogeneous and isotropic porous medium, into a sheetpile cofferdam; the interface is assumed to be sharp and the lower fluid stationary. The solution is obtained using the inverse hodograph. Numerical results are presented in nondimensional form for various parametric conditions in the physical plane; the interface pattern, as also the seepage discharge and exit gradient distribution are shown. The critical conditions of the interface are studied.

A conditional random field-based downscaling method for assessment of climate change impact on multisite daily precipitation in the Mahanadi basin

Downscaling to station-scale hydrologic variables from large-scale atmospheric variables simulated by general circulation models (GCMs) is usually necessary to assess the hydrologic impact of climate change. This work presents CRF-downscaling, a new probabilistic downscaling method that represents the daily precipitation sequence as a conditional random field (CRF). The conditional distribution of the precipitation sequence at a site, given the daily atmospheric (large-scale) variable sequence, is modeled as a linear chain CRF. CRFs do not make assumptions on independence of observations, which gives them flexibility in using high-dimensional feature vectors. Maximum likelihood parameter estimation for the model is performed using limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) optimization. Maximum a posteriori estimation is used to determine the most likely precipitation sequence for a given set of atmospheric input variables using the Viterbi algorithm. Direct classification of dry/wet days as well as precipitation amount is achieved within a single modeling framework. The model is used to project the future cumulative distribution function of precipitation. Uncertainty in precipitation prediction is addressed through a modified Viterbi algorithm that predicts the n most likely sequences. The model is applied for downscaling monsoon (June-September) daily precipitation at eight sites in the Mahanadi basin in Orissa, India, using the MIROC3.2 medium-resolution GCM. The predicted distributions at all sites show an increase in the number of wet days, and also an increase in wet day precipitation amounts. A comparison of current and future predicted probability density functions for daily precipitation shows a change in shape of the density function with decreasing probability of lower precipitation and increasing probability of higher precipitation.

Assimilation of remote sensing and hydrological data using adaptive filtering techniques for watershed modelling

The knowledge of hydrological variables (e. g. soil moisture, evapotranspiration) are of pronounced importance in various applications including flood control, agricultural production and effective water resources management. These applications require the accurate prediction of hydrological variables spatially and temporally in watershed/basin. Though hydrological models can simulate these variables at desired resolution (spatial and temporal), often they are validated against the variables, which are either sparse in resolution (e. g. soil moisture) or averaged over large regions (e. g. runoff). A combination of the distributed hydrological model (DHM) and remote sensing (RS) has the potential to improve resolution. Data assimilation schemes can optimally combine DHM and RS. Retrieval of hydrological variables (e. g. soil moisture) from remote sensing and assimilating it in hydrological model requires validation of algorithms using field studies. Here we present a review of methodologies developed to assimilate RS in DHM and demonstrate the application for soil moisture in a small experimental watershed in south India.

Optimizing a piezometric network in the estimation of the groundwater budget: a case study from a crystalline-rock watershed in southern India

An estimate of the groundwater budget at the catchment scale is extremely important for the sustainable management of available water resources. Water resources are generally subjected to over-exploitation for agricultural and domestic purposes in agrarian economies like India. The double water-table fluctuation method is a reliable method for calculating the water budget in semi-arid crystalline rock areas. Extensive measurements of water levels from a dense network before and after the monsoon rainfall were made in a 53 km(2)atershed in southern India and various components of the water balance were then calculated. Later, water level data underwent geostatistical analyses to determine the priority and/or redundancy of each measurement point using a cross-validation method. An optimal network evolved from these analyses. The network was then used in re-calculation of the water-balance components. It was established that such an optimized network provides far fewer measurement points without considerably changing the conclusions regarding groundwater budget. This exercise is helpful in reducing the time and expenditure involved in exhaustive piezometric surveys and also in determining the water budget for large watersheds (watersheds greater than 50 km(2)).

Optimal Reservoir Operation for Flood Control Using Folded Dynamic Programming

Folded Dynamic Programming (FDP) is adopted for developing optimalnreservoir operation policies for flood control. It is applied to a case study of Hirakud Reservoir in Mahanadi basin, India with the objective of deriving optimal policy for flood control. The river flows down to Naraj, the head of delta where a major city is located and finally joins the Bay of Bengal. As Hirakud reservoir is on the upstream side of delta area in the basin, it plays an important role in alleviating the severity of the flood for this area. Data of 68 floods such as peaks of inflow hydrograph, peak of outflow from reservoir during each flood, peak of flow hydrograph at Naraj and d/s catchment contribution are utilized. The combinations of 51, 54, 57 thousand cumecs as peak inflow into reservoir and 25.5, 20, 14 thousand cumecs respectively as,peak d/s catchment contribution form the critical combinations for flood situation. It is observed that the combination of 57 thousand cumecs of inflow into reservoir and 14 thousand cumecs for d/s catchment contribution is the most critical among the critical combinations of flow series. The method proposed can be extended to similar situations for deriving reservoir operating policies for flood control.

Reservoir performance under uncertainty in hydrologic impacts of climate change

Relatively few studies have addressed water management and adaptation measures in the face of changing water balances due to climate change. The current work studies climate change impact on a multipurpose reservoir performance and derives adaptive policies for possible futurescenarios. The method developed in this work is illustrated with a case study of Hirakud reservoir on the Mahanadi river in Orissa, India,which is a multipurpose reservoir serving flood control, irrigation and power generation. Climate change effects on annual hydropower generation and four performance indices (reliability with respect to three reservoir functions, viz. hydropower, irrigation and flood control, resiliency, vulnerability and deficit ratio with respect to hydropower) are studied. Outputs from three general circulation models (GCMs) for three scenarios each are downscaled to monsoon streamflow in the Mahanadi river for two future time slices, 2045-65 and 2075-95. Increased irrigation demands, rule curves dictated by increased need for flood storage and downscaled projections of streamflow from the ensemble of GCMs and scenarios are used for projecting future hydrologic scenarios. It is seen that hydropower generation and reliability with respect to hydropower and irrigation are likely to show a decrease in future in most scenarios, whereas the deficit ratio and vulnerability are likely to increase as a result of climate change if the standard operating policy (SOP) using current rule curves for flood protection is employed. An optimal monthly operating policy is then derived using stochastic dynamic programming (SDP) as an adaptive policy for mitigating impacts of climate change on reservoir operation. The objective of this policy is to maximize reliabilities with respect to multiple reservoir functions of hydropower, irrigation and flood control. In variations to this adaptive policy, increasingly more weightage is given to the purpose of maximizing reliability with respect to hydropower for two extreme scenarios. It is seen that by marginally sacrificing reliability with respect to irrigation and flood control, hydropower reliability and generation can be increased for future scenarios. This suggests that reservoir rules for flood control may have to be revised in basins where climate change projects an increasing probability of droughts. However, it is also seen that power generation is unable to be restored to current levels, due in part to the large projected increases in irrigation demand. This suggests that future water balance deficits may limit the success of adaptive policy options. (C) 2010 Elsevier Ltd. All rights reserved.

Nonlinear ensemble prediction of chaotic daily rainfall

The significance of treating rainfall as a chaotic system instead of a stochastic system for a better understanding of the underlying dynamics has been taken up by various studies recently. However, an important limitation of all these approaches is the dependence on a single method for identifying the chaotic nature and the parameters involved. Many of these approaches aim at only analyzing the chaotic nature and not its prediction. In the present study, an attempt is made to identify chaos using various techniques and prediction is also done by generating ensembles in order to quantify the uncertainty involved. Daily rainfall data of three regions with contrasting characteristics (mainly in the spatial area covered), Malaprabha, Mahanadi and All-India for the period 1955-2000 are used for the study. Auto-correlation and mutual information methods are used to determine the delay time for the phase space reconstruction. Optimum embedding dimension is determined using correlation dimension, false nearest neighbour algorithm and also nonlinear prediction methods. The low embedding dimensions obtained from these methods indicate the existence of low dimensional chaos in the three rainfall series. Correlation dimension method is done on th phase randomized and first derivative of the data series to check whether the saturation of the dimension is due to the inherent linear correlation structure or due to low dimensional dynamics. Positive Lyapunov exponents obtained prove the exponential divergence of the trajectories and hence the unpredictability. Surrogate data test is also done to further confirm the nonlinear structure of the rainfall series. A range of plausible parameters is used for generating an ensemble of predictions of rainfall for each year separately for the period 1996-2000 using the data till the preceding year. For analyzing the sensitiveness to initial conditions, predictions are done from two different months in a year viz., from the beginning of January and June. The reasonably good predictions obtained indicate the efficiency of the nonlinear prediction method for predicting the rainfall series. Also, the rank probability skill score and the rank histograms show that the ensembles generated are reliable with a good spread and skill. A comparison of results of the three regions indicates that although they are chaotic in nature, the spatial averaging over a large area can increase the dimension and improve the predictability, thus destroying the chaotic nature. (C) 2010 Elsevier Ltd. All rights reserved.

Mahanadi streamflow: climate change impact assessment and adaptive strategies

Impacts of climate change on hydrology are assessed by downscaling large scale general circulation model (GCM) outputs of climate variables to local scale hydrologic variables. This modelling approach is characterized by uncertainties resulting from the use of different models, different scenarios, etc. Modelling uncertainty in climate change impact assessment includes assigning weights to GCMs and scenarios, based on their performances, and providing weighted mean projection for the future. This projection is further used for water resources planning and adaptation to combat the adverse impacts of climate change. The present article summarizes the recent published work of the authors on uncertainty modelling and development of adaptation strategies to climate change for the Mahanadi river in India.

Hills, dams and forests. Some field observations from the Western Ghats

Man’s attempts to intensify the use of natural resources can often result in the exhaustion of the resource or deterioration of other interacting resources. The single-minded pursuit of the development of the water resources of the rivers of the Western Ghats shows many examples of this view, particularly in the unnecessary destruction of the dwindling forest resources. This destruction may be caused by (i) problems o f rehabilitation, e.g. the Ramanagar settlement of the Kalinadi project (ii) the impact of labourers, e.g. the destruction of evergreen sholas on the Upper Nilgiri plateau (iii) the access to encroachers and poachers, e.g. Panshet and Kalinadi (iv) faulty planning, e.g. Linganamakki and Kalinadi. This destruction of forest cover has had a number of deleterious consequences in (i) worsening the shortages of forest resources, (ii) hastening the siltation of the reservoirs, (iii) ecological imbalances as in the rapid spread ofEupatorium in the Kalinadi project area and (iv) the decimation of biological diversity, as in the great reduction of evergreen forests in the Western Ghats, threatening the survival of lion-tailed macaque and the extinction of grass species,Hubbardia heptaneuron. It is stressed that the only sustainable and therefore true development is environmentally sound development. The interests of the weaker sections of the society often provide a good index of the soundness of the development from an environmental point of view. The planning of the development process with this perspective is a great scientific and technological challenge that must be taken up.