Many water resources problems are best tackled by testing the simulated performance of alternative designs in relation to representative sequences of hydrological input in the system. For the purpose of simulation, usually a hydrograph covering a period of 50 years of monthlyriver flows is required at each key point of interest in the system. Getting this length of reliable and continuous river flow data in most countries is difficult as streamflow observations are rather sparse and good records cover relatively short periods. In order to remedy the situation, the rainfall-runoff modelling approach is often used to make up for the missing data and satisfy the minimum record length requirement. Rainfall-runoff modelling often provides a solution because precipitation records normally extend back much further than flow records. This is due to the relative ease of making precipitation measurements as compared to setting up a discharge measuring station. Raingauges are easy to install with a much greater flexibility of choice of site which can be conveniently located near a centre of human activity thus facilitating operation and maintenance. River gauging stations on the other hand, must be located at hydraulically acceptable sites which are often remotely located, with gauge plates often being susceptible to damage or lack of maintenance. Gauging stations also require calibration through the establishment of rating curves which may require many years to adequately cover the range of stage variations. These requirements, added to the fact that resources in terms of both human and material costs are limited, has led to the situation where there are fewer river gauging stations with relatively shorter records while precipitation stations are numerous and have longer records (Shawinigan, 1993):
exposure to the pollutants in the Kafueriver. Although numerous investigations have suggested that expression of CYP 1-4 isoenzymes in animals is altered by xenobio- tics including environmental contaminants, and has the potential to be indicative of the exposure to these chemi- cals , there is lack of information on the characteriza- tion, sequencing and mRNA expression levels of CYP 450s in Kafue lechwe and its application. Due to the gaps in information about nucleotide and/or amino acid se- quence of CYP1A1 and CYP3A in Kafue lechwe, the genes were sequenced and the results provided insights on the evolution of these genes. The partial nucleotide sequences of lechwe CY lAl and CYP3A were success- fully characterized and their sequences determined and by studying the homology of the sequenced lechwe CYP1A1 with CYP1A1 of other animals, lechwe CYP1A1 showed higher similarities with CYP1A1 of sheep (98%) and cattle CYP1A1 (97%). The CYP3A lechwe sequence shared higher identities with CYP3A24 of sheep (97%) and CYP3A24 of cattle (95%). The re- sults are in agreement with the phylogenetic analyses which confirmed the two novel lechwe genes to be part of the CYP1A1 and CYP3A24 genes. These results pos- sibly suggest that the lechwe CYP1A1 and CYP3A24 genes could have evolved from the same ancestor with
Abstract: Rainfallrunoff modelling is the first step in water resources management. It is the only way to simulate the hydrological behavior of the basin for a good evaluation of the potentiality of this in term of water production. Many approaches are actually in use. In physically distributed models, deterministic relations issued from conservation laws of physics (mass conservation, moment momentum conservation) are solved to describe the hydrological processes generating flow and their interaction. A DEM that should be as complete as possible is associed. Complexity of the equations to be solved and the huge amount of required data, uncertainty in these data make these models of limited use. Conceptual rainfall-runoff models are often preferred by hydrologists. These models are based on equations relating in a realistic manner the different terms of the hydrological cycle. They are simpler than determistic models and more flexible, Conceptual models are generally global. According to the way hydrological cycle terms are taken into account, conceptual model can be classified as empirical or not. The aim of this paper is to evaluate the availability of water in the Koulountou riverbasin, a tributary of Gambia River. This riverbasin should reinforce the water resource in a neighboring Kayanga riverbasin. Two empirical models at daily and monthly scale, the GR4J and GR2M have been used to describe the hydrological behavior of this basin. These models have been realized by the CEMAGREF, a French research Office. They use as inputs daily or monthlyrainfall and potential evapotranspiration and riverbasin area, and give as output daily or monthlyrunoff. The first step before applying a hydrological model is to calibrate it that is to estimate the best parameters that fit the outputs in a given period. The Nash criterion has been used as goodness-of-fit criterion. Model performs satisfactory when this criterion is greater than 0.70 according to available data. A period from 1971 to 1994 has been selected. This period have been divided into three parts: one for calibration (1971-1978), one for validation (1978-1986), and the last for application (1987-1994). The results we obtain shows that GR4J and GR2M performs well in the Koulountou riverbasin since the Nash criterion is greater than 0.8.
The first order moment of the Moselle discharge data are plotted against basin area in a double logarithmic diagram in Fig. 2 in accordance with the traditional way of representing scale dependences. There is a tendency that the data cluster around straight lines but the scatter is quite large. The first order moments (the long term mean values) do not depend on duration D but higher order moments do. This spatial- temporal dependence for the second order moment is illus- trated in Fig. 3 in terms of the coefficient of variation. For short durations (an hour and a day) this coefficient shows a strong decay with the area. This dependence on area de- creases with the increase in duration and for annual values it is negligible. For small catchments the estimated values dif- fer between one hour and one day duration. This difference almost disappears for basins bigger than 1000 km 2 .
Abstract—This paper presents a large scale hydrological model for the Fitzroy Basin using the MIKE 11 NAM modelling system. This model simulates the rainfallrunoff processes for the three different and interrelated storages which are surface storage, root zone storage and groundwater storage. The parameters of such model cannot be obtained directly from measurable quantities of catchment characteristics. Hence model calibration is required to get the model parameters. Manual calibration is very time consuming and it only focuses on a single objective function. Thus tradeoff exists between the different objectives. For this study, an automatic calibration was done considering the four multiple objectives and obtained the optimal values of the model parameters for each catchment. The simulated and observed discharge hydrographs show a reasonable good match for each sub-catchment. Moreover model reliability was evaluated using the statistical methods Index of Agreement (IA) and Efficiency Index (EI). The IA and EI obtained 0.821-0.951 and 0.849-0.961 for different sub-catchments.
method is 608 mm. Fig. 2 shows the distribution of mean areal rainfall and location of three raingauge sites surrounding the basin. Main stream of the Shivganga River originates in the heavy rainfall zone, whereas Shindewadi and Degaon sub basins heads in the medium to low rainfall zone in the eastern part of the basin. The orographic effect of the Singhgad-Katraj hill range in the western part is responsible for enhancing the higher monsoon rainfall. In addition to this, the geographical location and the east-west orientation of the Shivganga Basin also determines the distribution of rainfall over the entire basin. Thus spatial variation of rainfall is controlled by orographic effect on one side and the east west orientation of basin on the other, which is reflected in the isohyetal pattern of the basin. The isohyetal pattern (Fig. 2) displays a marked spatial variation in the basin form west to east. The source areas of Kondhanpur, Kelawade sub basin receive more than 800 mm rainfall. The amount of rainfall gradually decreases towards east (Degaon, Shindewadi) i. e. less than 600 mm. However, in this part, the drainage area is very less. The area of lowest rainfall (<500 mm) is situated along the eastern divide margin of Karha-Saswad plateau The seasonal pattern is almost similar to the annual distribution of rainfall, since more than 90% of the annual rainfall is concentrated during the monsoon season.
Water is a fundamental requirement in the life of human beings. History revels that most of the civilization started very close to rivers banks due to proximity of water satisfying their demands for various purposes. The estimation of spatial-temporal availability of water in a region is an essential part of the water resources planning. Models are being used in several regions of the world for water resources planning and development. The SWAT is one such model used most frequently for this purpose. Bhadra River is one of the major stream of Tungabhadra, which originates in the Western Ghats of Karnataka. The Bhadra basin is a principle water source for irrigation and domestic supply to Shimogga, Davanagere and Bellary districts. It has been reported in the recent past that, the project which are on this river is not getting expected amount of water and due to which the committed demands are not met. In addition to this, the Inter-Governmental
Since snow accumulation and ablation is influenced by energy balance in the process of transforming to ru- noff, temperature can be considered, in fact, as the significant melting parameter. Temperature data are meas- ured by meteorological stations at a certain elevation in which the gages are installed. Since temperature varies with elevation, therefore, temperature elevation relationship helps to estimate the temperature at the unmeasured locations . Previous studies have utilized different methods to estimate climatic factors. Dey et al. presented the application of SRM in the Western Himalayas. They used ambient air temperature values from one climate station outside of the basin and degree-day values determined by extrapolating the ambient air temperature to the mean elevation according to certain temperature lapse rates . At the current study, temperature data rec- orded from five different stations at different elevation levels were applied to obtain zonal temperature by extrapolating the station altitude to mean zone altitude with a certain temperature lapse rate. The relation be- tween elevation and daily average temperature was developed for different stations as given in Figure 4. Tem- perature laps rate estimated is 5.1˚C/km.
relation has become a very interesting topic among the researchers as the quantity and rate of runoff has become some of the main factors in planning and management of water resources in proper sustainable scientific way, because the quantity or rate of social activities have resulted increased and diversified the demand of water from the basin. Due to many human activities both in the use for personal and commercial has led to increase in demand for water. As the quantity of water in the catchment, discharge of the springs and streams are reducing day by day. There is a need for preservation of water. Soil and Water Assessment Tool known as SWAT. SWAT is the tool that is used for modeling of the rainfallrunoff relation of the watershed.
industrialization, energy use, irrigation integrated with advances in agriculture productivity, desertification, global warming and poor water quality have made water, a scarce resource in the country. Water management in India in future must shift its emphasis from social good as at present to economic good, and use of market mechanisms with the participation of the business sector. Such a change will achieve a more efficient and effective allocation, use and management of water, and their roles of both public and private sectors in managing water resources must be defined. Therefore, both development and management of water resources with scientific data base is a pre-requisite for achieving sustainable development. Application of models has become an indispensable tool for the understanding of the hydrological processes occurring at the watershed scale as the models provide accurate estimate of components of water balance thereby availability of water resources. This report explains the application of hydrological models for one combined basin (Brahmani-Baitarni) and compares the results with observed data to assess the model performance. Soil Water Assessment Tool (SWAT) which is semi- empirical and semi-physical watershed scale model use as micro scale. SWAT consists of major water budget components such as weather, surface runoff, return flow, percolation, evapotranspiration, transmission losses, pond and reservoir storage, crop growth, irrigation water transfer, groundwater flow, and channel routing.
These early developments employed convolution to route direct runoff (and drainage to recharge) to the basin outlet, using the probability-distributed principle applied to the time-of-travel to the catchment outlet. Specifically, the probability density function (pdf) of translation time was taken as equivalent to the kernel function or instantaneous unit hydrograph. Invoking a pdf of inverse Gaussian form provided a physical link with the St. Venant equations of open-channel flow and the convection-diffusion equation. It was not until 1986 that the model schematic of Fig. 1 first appeared (see Fig. 3 of Moore, 1986). The parallel routing formulation made explicit by this schematic was inspired by the simplified catchment model schematic of Dooge (Fig. 1-8 in Dooge, 1973; Fig. 2.3 in Dooge and OKane, 2003). Here, soil moisture feedback controls the partitioning of the direct storm and groundwater response of total runoff, deliberately avoiding the less identifiable separation of overland flow and interflow. Convolution was replaced by non-linear storage routing as being simpler and easier to update for real-timeapplication. The exposition of the Horton-Izzard equation in Dooge (1973), and reference to the source and related texts, provided the foundation for the recursive solutions to this equation used for storage routing in the PDM (Moore, 1983); Moore and Bell (2002) provides further details and reference sources. This was supplemented by the transfer function representation of a cascade of two linear reservoirs efficiently parameterised via one or two storage coefficients (OConnor, 1982) as a further routing option.
A recovery of ancient records of the Como Lake water levels at the Fortilizio in Lecco hydrometric station enabled the reconstruction of a time series of daily water level and runoff from the Como Lake spanning the 1845-2014 period. In parallel, the monthly areal precipitation at the Adda river catchment scale was estimated for the same 170 years- long period. This time series, which is one of the longest available for Italian riverbasins will support analyses of the reasons of changes in the runoff regime in response to climatic and anthropogenic changes. A comparison of the two series applying the Mann- Kendall, Spearman and Theil-Sen trend tests, shows a decline, in the long term, of runoff and a more significant one of precipitation. Because some changes in the operation at the outlet of the Como Lake occurred after 1946 and also in the storage capacity of the upstream reservoirs the time series was splitted in two periods, before and after 1946. The results of the statistical tests for both precipitation and runoff in three time periods are consistent, but only for the time series of annual runoff the decline is statistically significant with 5% significance level. To analyse if changes occurred at different time scales the wavelet transform was applied to the daily runoff series. Finally the Fourier power spectrum of the the daily runoff data shows a signal of higher energy corresponding to a period between 11 and 13 years, close to the sunspots cycle period, and its significance is under investigation.
In this study, calculations are executed with average AMC conditions (AMC II), Chow et al. , Neitsch et al. . The prime concern was to vary the value of initial abstraction ratio (λ). The values of λ were taken 0.1, 0.15, 0.20 and 0.25 to find out the best fit for the hydrological study of Bina basin. For convenience in practical applications, S is mapped into a dimensionless parameter CN, curve number, (SCS ). The equation is expressed as:
While the availability of hydrological (e.g., flow) data is crucial for water resources planning and management, most rivers in developing countries, including China, do not have sufficient data partially due to poorly main- tained monitoring networks [1-3]. In addition, it is al- most impractical to monitor all subbasins of interest within large basins , such as the 54,805 km 2 Hailar Riverbasin located in northeastern China. Thus, re- searchers developed and/or used various methods to es- timate runoff from ungauged basins/subbasins. Those methods include sophisticated simulation models as well as simple statistics models. In practice, simple models
Figure 1. “Limits” concept used for water partitioning in DWBM. The concept is used to partition both the precipitation (P) between wetting (W) and direct runoff, and the wetting between evapotranspiration (ET) and storage. The α parameters determine how close the variables are from their limits (dashed lines). 3
whereas changes in precipitation were more noticeable earlier in the time series. Human activities were shown to be the main driving force behind these changes. Our findings are in agreement with those of previous studies (e.g. Gao, et al., 2002; Yao et al., 2003; Cui and Cui, 2007) and suggest that human activities have had a greater impact than climate change on the hydrology of the Weihe Riverbasin. Given the changing environment, further work on runoff variation for hydrographic computation in engineering is necessary.
An excess or a lack of rainfall are the major causes of most hydrological hazards, and the need for a systematic approach to river flow forecasting based on rainfall is imperative, especially in Nigeria. A study was carried out on three major gauging stations of the Ogun riverbasin to determine the rainfall-discharge relationship and model equations for use in the basin and similar basins. Stream flow and rainfall data for at least seven consecutive years for each station were collected and analyzed. The rainfall-runoff data were subjected to linear, exponential and higher order analysis. Stream flow data were also fitted to normal, log-normal and log-Pearson Type III distributions. The selection of the appropriate probability distribu- tion model for each gauging station was based on graphical comparisons between observed and predicted flows and goodness-of-fit tests using chi-square and probability correlation coefficients. Results show that model equations with logarithmic and exponential relationships between rainfall and discharge gave better and more realistic prediction estimates and can be used for the basin. It was determined that the peak discharges occurred when the rainfall values were at their maximum, and a distinct relationship between the discharge and rainfall exists at each of the gauging stations.
The thrust of the study was that social-ecological typologies undergo change over time. These changes can be slow and predictable, or they may be fast and unforeseen. Thus, the use of a timeline helped to reveal the longer-term disturbances or shocks related to KafueRiver floods, flow and flux on pastoralism since 1978, after the construction of the ITT dam. Thus, long term trend analysis was used to explore historical patterns to capture all major social-ecological disturbances using seasonal calendars. Seasonal calendars are useful tools in rural areas in identifying different activities throughout the year (s), for example production activities, hazards and stresses, periods of hunger, landuse, erosion, rainfall, population, management of common property resources etc. (Kirsrten et al., 2002; Matata et al., 1999). In this study, seasonal calendars were drawn to foster understanding of local pastoral systems and trace changes in grazing/water patterns. For this, pastoralists illustrated patterns month by month, cropping patterns, water use, livestock transhumance, pests and cattle diseases. Further, Focus Group Discussions supplemented seasonal calendars by using transect walks and photo voice process. A transect walk is a simple technique used in rural typological studies to ensure that the researcher, together with local pastoralists, explore the spatial differences fully in the area under study (Matata et al., 1999; Mettrick, 1993). In addition, an essential component was photo voice process (Cunningham et al., 2009), in which pastoralists took photographs of what they thought was important about a given social-ecological issue, and then had lengthy interview about the context and motivation in taking each picture. This was followed by transect walks to map locations found in the photos (e.g. grazing lands and water points) and related these to climate variability and change. This gave an opportunity to locals to show outsiders how they used the floodplain for their livelihoods and the flooding patterns (seasonal and dam-induced).
The River Mamoré in Bolivia, a major tributary of the Amazon, floods annually causing considerable damage, especially to cattle ranches and villages in the area. To limit the effects of flooding in Bolivia the Bolivian Vice-Ministry for Water Management and the Dutch Embassy together initiated the program ‘Vivir con el Agua’ (living with water). A part of the program is to set up a Flood Early Warning System, FEWS, which will warn inhabitants of any flood danger and give them time to take measures to limit the damage. This FEWS-project in Bolivia is being carried out by the consortium including RoyalHaskoningDHV, Deltares and the local organization Centro Agua Bolivia. During the FEWS project in Bolivia the curiosity arose how a semi-distributed hydrological model like HBV will perform in forecasting the discharge in this basin area, instead of the physically-based, distributed parameter, basin hydrological model TOPOG, used in the project.