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In the present study, Artificial Neural Networks (ANNs) and Genetic Programming (GP) soft-computing models were established to estimate streamflow in Tel River Basin, Odisha, India. In most of the ...

Land use (LU) or land cover (LC) is a critical factor dictating the amount of available water in runoff and groundwater. LU/LC Land use (LU) or land cover (LC) is a critical factor which ca...

Monthly stream flow forecasting can provide crucial information on hydrological applications including water resource management and flood mitigation systems. In this statistical study, tim...

In this study, estimation of discharge and uncertainty analysis of streamflow estimation is done for the Barak River basin using Soil and Water Assessment Tool (SWAT) and sequential uncertainty dom...

In the majority of small urban catchments, there is a problem with obtaining precipitation data necessary for hydrological applications and analyses in the scope of assessing flood risk. One of the means of measuring rainfall depth is to make use of weather radar technology, which provides information on the spatial and temporal distribution of rainfall in a catchment. In the work, the dependency between radar reflectivity (Z) and rainfall rate (R) was determined on the basis of a few events measured at two precipitation stations located in the Służewiecki Stream catchment in Warsaw, Poland. Making use of the Z-R relationship as well as values of radar reflectivity, the amount of rainfall for the analysed event was calculated and compared with the amounts of rainfall measured using rain gauges. Relatively good compatibility between the rainfall totals was obtained for the majority of events. Rainfall depths obtained for two selected events on the basis of data from the weather radar were applied to simulate flows in the analysed catchment using the SWMM (Storm Water Management Model) hydrodynamic model. Values of the relative error calculated on the basis of measured flows and flows calculated in reaction to rainfalls estimated using the Z-R relationship were, in the majority of cases, lower than 25%. Simulations carried out on the SWMM model for a few rainfall scenarios in response to rainfall depth measured at precipitation stations and estimated on the basis of radar data revealed the possibility of the occurrence of flooding in the catchment as a result of the overflow of rainfall collectors.

Combinations of low-frequency components (also known as approximations) resulting from the wavelet decomposition are tested as inputs to an artificial neural network (ANN) in a hybrid approach, and...

This study aimed to develop quantitative relationships for Maori cultural values supported by streamflow. We examined the results of a Cultural Flow Preference Study (CFPS) for five streams in Cant...

We directly compare trip willingness to pay (WTP) values between dichotomous choice contingent valuation (DCCV) and discrete choice experiment (DCE) stated preference surveys of private party Grand Canyon whitewater boaters. The consistency of DCCV and DCE estimates is debated in the literature, and this study contributes to the body of work comparing the methods. Comparisons were made of mean WTP estimates for four hypothetical Colorado River flow-level scenarios. Boaters were found to most highly value mid-range flows, with very low and very high flows eliciting lower WTP estimates across both DCE and DCCV surveys. Mean WTP precision was estimated through simulation. No statistically significant differences were detected between the two methods at three of the four hypothetical flow levels.

Many catchments in India are devoid of gauging stations. In the absence of measurements of stream flow, regional rainfall-runoff relationships developed over a hydro-meteorologically similar region...

Small water bodies, such as ponds and wetlands, are common landscape features, but often are not simulated within a watershed modeling framework. The wetland modeling tool, AgWET, uses a GIS framew...

Human impacts on rivers threaten the natural function of riverine ecosystems. This paper assesses how channel confinement affects the scour depth and spatial extent of bed disturbance and discusses...

Accepter l’existence du concept d’equifinalite c’est reconnaitre l’incertitude liee a l’existence d’une famille de solutions donnant des resultats de qualite similaire obtenus avec la meme fonction objectif. Malgre l’existence de methodes de caracterisations de cette incertitude, le modele hydrologique HYDROTEL a ete principalement utilise jusqu’a maintenant selon le paradigme du calage optimal unique sans evaluer a posteriori les consequences de ce choix. Cette etude propose d’evaluer l’impact du choix du jeu de parametres optimises sur certaines variables et indicateurs hydrologiques simules, a savoir: (1) les debits journaliers; (2) les debits d’etiage a 7 et 30 jours et les debits maximum; (3) l’equivalent en eau de la neige (EEN); (4) les variations du contenu en eau du sol peu profond; et (5) l’evapotranspiration reelle. Dans ce contexte, HYDROTEL est mis en place sur 10 bassins versant du Quebec meridional entre 1982 et 2002. Pour chacune des fonctions objectif (FO; Kling–Gupta efficiency et Nash-log) et chacun des bassins, l’algorithme dynamically dimensioned search (DDS) dispose d’un budget de 5000 repetitions pour optimiser les 12 parametres de calage d’HYDROTEL sur 1981–1991. Ainsi, 250 jeux de parametres sont conserves pour evaluer l’incertitude parametrique et l’equifinalite resultante. Les resultats de calage indiquent des fonctions objectif comprises entre 0.75 et 0.95, tandis que pour chaque modele les 250 meilleures repetitions presentent des fonctions objectif egales a 1% pres. Globalement, pour tous les processus simules excepte pour l’EEN, l’incertitude relative aux FO etait plus importante que celle relative aux jeux de parametres. Cependant, les resultats saisonniers suggerent que l’incertitude parametrique peut depasser celle due aux FO dans certaines conditions particulieres. Elle devra donc etre prise en compte, en particulier pour les etudes d’impacts et de risque hydrologique dont les variables d’interet sont principalement des indicateurs hydrologiques simules et non pas les debits journaliers. Abstract Accepting the concept of equifinality may result in larger uncertainty associated with model predictions than that of the optimal parameter set paradigm. Despite the existence of uncertainty characterization methods, the semi-distributed hydrological model HYDROTEL has been used within the latter paradigm. What is the impact of hypothesizing an optimal parameter set? This paper focuses on the assesment of the impact of equifinality of calibration parameters with respect to modelled hydrological variables and indices, namely: (1) daily flows; (2) seasonal 7- and 30-day low flows, and maximum flow; (3) snow water equivalent (SWE); (4) shallow ground water variations; and (5) actual evapotranspiration. This assessment is presented for 10 southern Quebec watersheds of the St. Lawrence River. The watershed models were calibrated and validated for 1982–1991 and 1991–2002, respectively. Automatic calibration was performed using the dynamically dimensioned search (DDS) algorithm based on the maximization of two objective functions (OFs): (1) the Kling–Gupta efficiency and (2) the Nash-log. DDS was executed to calibrate 12 hydrological parameters for one optimization trial for each watershed and each OF with a budget of 5000 model runs. To analyze parameter uncertainty and resulting equifinality, 250 sets of parameters were extracted from each trial run. Calibration performances for both OFs were between 0.75 and 0.95, while the selected 250 best sets of parameters had OF values differing by less than 1%. Results showed that the overall OF uncertainty was larger than the parameter uncertainty for all modelled processes except the SWE. Nevertheless, seasonal results suggested parameter uncertainty could be greater than OF uncertainty for specific seasons or years, although it was not possible to make a general outcome stand out. In particular for impact studies where the variables of interest are not daily flows but rather hydrological indices or variables, parameter uncertainty will need to be accounted for.

Glacierized mountains are often referred to as our world's water towers because glaciers both store water over time and regulate seasonal stream flow, releasing runoff during dry seasons when societies most need water. Ice loss thus has the potential to affect human societies in diverse ways, including irrigation, agriculture, hydropower, potable water, livelihoods, recreation, spirituality, and demography. Unfortunately, research focusing on the human impacts of glacier runoff variability in mountain regions remains limited, and studies often rely on assumptions rather than concrete evidence about the effects of shrinking glaciers on mountain hydrology and societies. This article provides a systematic review of international research on human impacts of glacier meltwater variability in mountain ranges worldwide, including the Andes, Alps, greater Himalayan region, Cascades, and Alaska. It identifies four main areas of existing research: (1) socioeconomic impacts; (2) hydropower; (3) agriculture, irrigation, and food security; and (4) cultural impacts. The article also suggests paths forward for social sciences, humanities, and natural sciences research that could more accurately detect and attribute glacier runoff and human impacts, grapple with complex and intersecting spatial and temporal scales, and implement transdisciplinary research approaches to study glacier runoff. The objective is ultimately to redefine and reorient the glacier-water problem around human societies rather than simply around ice and climate. By systematically evaluating human impacts in different mountain regions, the article strives to stimulate cross-regional thinking and inspire new studies on glaciers, hydrology, risk, adaptation, and human–environment interactions in mountain regions.

Effler SW, Prestigiacomo AR, Hairston NG, Auer MT, Kuczynski A, Chapra SC. 2016. Dissolved phosphorus concentrations in Cayuga Lake system and differences from two analytical protocols. Lake Reserve Manage. 32:392–401.Differences in the concentrations of dissolved forms of phosphorus (P) measured with 2 widely used spectral protocols were documented and evaluated for Cayuga Lake, New York, and 4 of its primary tributaries. The analysis focuses on 2 operationally defined forms of dissolved P, soluble reactive P (SRP) and soluble unreactive P (SUP), which together constitute dissolved P (TDP). Direct comparisons were based on analysis of the results from the 2 protocols of split samples of year-round deep water representative of the entire water column during turnover and the respective dependencies of tributary concentrations on stream flow. Although the TDP concentrations converged for the 2 protocols, there were systematic differences for the contributions of SRP versus SUP (i.e., one protocol y...

Methods based on the recursive probability, the extreme number theorem, and Markov chain (MC) concepts were applied to predict drought lengths (duration) on the standardized (termed as standardized hydrological index, SHI) sequences of monthly and annual river flows from Atlantic Canada. Results of the study indicated that the MC-based method is the most efficient, reliable and versatile method for predicting drought durations followed by the extreme-number-based method. The recursive-probability-based method was found to be computationally intensive and less efficient, although it provided a powerful means for calibrating the empirical plotting position formula needed in the MC-based method. The Weibull plotting position formula turned out to be a suitable measure of the exceedance probability in MC methodology for predicting drought lengths in Atlantic Canada. Based on results, it can be inferred that the MC-based method can be extended to MC2 and higher-order chains for predicting drought lengt...

A modelling study is performed to evaluate interannual and decadal-scale streamflow variability into the Grand Ethiopian Renaissance Dam (GERD) reservoir and comparison of various filling strategies for hydropower and downstream releases to Sudan and Egypt from this dam. To capture these aspects, simulations of probabilistic streamflow via wavelet analysis are produced to define the propensity towards wetter or drier conditions for absolute, threshold and percentage-based filling strategies. Absolute filling strategies have lower uncertainty than percentage-based strategies, benefiting upstream planning; however, downstream releases may be near zero on occasion. Consensus among the riparian countries prior to initiation of filling is strongly encouraged.

The Hargreaves method provides reference evapotranspiration (ETo) estimates when only air temperature data are available, although it requires previous local calibration for an acceptable performance. This method was evaluated using the data from 71 meteorological stations in the Seolma-cheon basin (8.48 km2), South Korea, comparing daily estimates against those from the Penman‐Monteith (PM) method, which was used as the standard. To estimate reference ETo more exactly, considering the climatological characteristics in South Korea, parameter regionalization of the Hargreaves equation is carried out. First, the modified Hargreaves equation is presented after an analysis of the relationship between solar radiation and temperature. Second, parameter (KET) optimization of the regional calibration of the Hargreaves equation (RCH) is performed using the PM method and the modified equation at 71 meteorological stations. Next, an application was carried out to evaluate the evapotranspiration methods (PM, ...

Recent research has elucidated the acute lethal effects of elevated water temperatures to glochidia (larvae), juvenile, and adult life stages of freshwater mussels (Order Unionida), but few studies have focused on sublethal effects of thermal stress. We evaluated the sublethal effects of elevated temperature on burrowing behavior and byssus production in juveniles, and on enzymatic biomarkers of stress in adults in acute (96 h) laboratory experiments in sediment, with two acclimation temperatures (22 and 27 °C) and two experimental water levels (watered and dewatered) as proxies for flow regime. Increasing temperature significantly reduced burrowing in all five species tested, and the dewatered treatment (a proxy for drought conditions) reduced burrowing in all but Amblema plicata. Production of byssal threads was affected most drastically by flow regime, with the probability of byssus presence reduced by 93–99% in the dewatered treatment, compared to the watered treatment (a proxy for low flow conditions...

Stream flow prediction is crucial for water resource planning and management at the watershed scale. This study investigates various modelling approaches, namely, autoregressive integrated moving average, deseasonalized autoregressive moving average, artificial neural network (ANN), simulator for water resources in rural basins, and identification of hydrographs and components from rainfall, evaporation, and stream (IHACRES) models, to simulate and predict stream flow in Kasilian watershed in northern Iran. This research represents a case study on forest watershed modelling with the lack of enough hydro-meteorological data. The comparison of the prediction performance of the models was done based on some error estimation criteria. The results indicate that the ANN and IHACRES models perform better than the two other modelling approaches. The advantages and disadvantages of different hydrological models are discussed.

This study compares three different artificial intelligence approaches, namely, gene expression programming (GEP), adaptive neuro-fuzzy inference system (ANFIS) and artificial neural networks (ANNs), in daily stream flow forecasting of Alavian Dam Station on the Soofi-Cahi River in the Northwestern Iran. The study demonstrates that the optimal results were obtained from the triple-input models, including stream flows of current and 2 previous days, and that the GEP model performed better than the ANN and ANFIS models in daily stream flow forecasting. It was found that the optimal GEP model with coefficient of determination R 2 = 0.924, root mean square error = 0.908 m3/s and scatter index = 0.354 in the test stage was superior in forecasting daily stream flow to the optimal ANN and ANFIS models.

This paper investigates the ability of a least-squares support vector machine (LSSVM) model to improve the accuracy of streamflow forecasting. Cross-validation and grid-search methods are used to automatically determine the LSSVM parameters in the forecasting process. To assess the effectiveness of this model, monthly streamflow records from two stations, Tg Tulang and Tg Rambutan of the Kinta River in Perak, Peninsular Malaysia, were used as case studies. The performance of the LSSVM model is compared with the conventional statistical autoregressive integrated moving average (ARIMA), the artificial neural network (ANN) and support vector machine (SVM) models using various statistical measures. The results of the comparison indicate that the LSSVM model is a useful tool and a promising new method for streamflow forecasting. Editor D. Koutsoyiannis; Associate editor L. See Citation Shabri, A. and Suhartono, 2012. Streamflow forecasting using least-squares support vector machines. Hydrological Scie...

The concentrations of several pharmaceuticals and personal care products (PPCPs) were simulated in the Grand River watershed using the PhATE (Pharmaceutical Assessment and Transport Evaluation) model. PPCPs that were previously measured in the Grand River watershed were selected as the target compounds for this study. The application of the PhATE model was adapted to account for Canadian climatic conditions and its seasonal variability. In this regard, seasonal hydrological parameters (i.e., stream flow and velocity) were estimated based on historical data. Chemical loss parameters, including in-stream decay, human loss, and removal efficiency of treatment plants, were initially extracted from the literature and then calibrated to the site data. In general, the adapted PhATE model reasonably simulated pharmaceuticals with continuous use by humans such as ibuprofen, naproxen, carbamazepine, and gemfibrozil. Validation, which was performed only for ibuprofen, naproxen, and carbamazepine suggests that the ca...

The Canadian Prairie drought of 1999–2005 negatively affected several activities including agriculture, stream flow, hydro-electric production and forest fires. However, surface drought conditions and associated impacts were neither spatially nor temporally uniform. Following an assessment of several gridded temperature and precipitation datasets, this study incorporates the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI) to characterize the surface features of the 1999–2005 Prairie drought in terms of its origin, spatial propagation, persistence and termination. This includes the development and application of a newly proposed multi-stage concept to characterize and classify drought. These characteristics are then compared to previous major Prairie droughts in the instrumental record. Results show that the 1999–2005 drought originated in the Great Plains of the United States and expanded into southwestern Alberta in late 1999 to early 2000. It then intensified to cover...

Improperly designed stream crossing structures may alter the form and function of stream ecosystems and habitat and prohibit the movement of aquatic organisms. Stream sections adjoining five concrete box culverts, five low-water crossings (concrete slabs vented by one or multiple culverts), and two large, single corrugated culvert vehicle crossings in eastern Kansas streams were compared to reference reaches using a geomorphologic survey and stream classification. Stream reaches were also compared upstream and downstream of crossings, and crossing measurements were used to determine which crossing design best mimicked the natural dimensions of the adjoining stream. Four of five low-water crossings, three of five box culverts, and one of two large, single corrugated pipe culverts changed classification from upstream to downstream of the crossings. Mean riffle spacing upstream at low-water crossings (8.6 bankfull widths) was double that of downstream reaches (mean 4.4 bankfull widths) but was simil...

Accurate forecasting of streamflow is essential for the efficient operation of water resources systems. The streamflow process is complex and highly nonlinear. Therefore, researchers try to devise alterative techniques to forecast streamflow with relative ease and reasonable accuracy, although traditional deterministic and conceptual models are available. The present work uses three data-driven techniques, namely artificial neural networks (ANN), genetic programming (GP) and model trees (MT) to forecast river flow one day in advance at two stations in the Narmada catchment of India, and the results are compared. All the models performed reasonably well as far as accuracy of prediction is concerned. It was found that the ANN and MT techniques performed almost equally well, but GP performed better than both these techniques, although only marginally in terms of prediction accuracy in normal and extreme events. Citation Londhe, S. & Charhate, S. (2010) Comparison of data-driven modelling techniques ...

“Bizarre,” “monstrous”: in society as well as in science, this is the way we are used to describing objects that deviate from an expected standard. Hydrology is no exception. The bizarre or the monstrous describes every object that has a low probability of occurring, or that our models fail to represent. Actually, the bizarre or the monstrous is often a demonstration of the limits of our models rather than an intrinsic characteristic of the objects we study. This article provides a reflection on the definition of bizarre and monstrous in the context of hydrology. We base our reflection on 60 years of experience in hydrometeorological operational management and applied research at the French national electricity company (EDF-DTG). First, we describe several classical a priori models or conceptions trusted by hydrologists, sometimes erroneously. These include classical rainfall or streamflow measurement issues, certain limits of the watershed concept or problems in the spatialization of local measu...

The relationship between the interannual changes in streamflow, precipitation and temperature of the Murray-Darling basin is investigated by using a two-parameter climate elasticity of streamflow approach. The non-linear relationship between streamflow and both precipitation and temperature indicates a greater streamflow sensitivity to precipitation than to temperature but a more significant impact of temperature change on streamflow than previously reported. The physical mechanisms producing high streamflow sensitivity to temperature change are not well understood, but may relate to concurrent changes in sub-annual precipitation characteristics such as seasonality, spatial distribution and intensity. Thus these characteristics need to be assessed and accounted for when attempting to project how streamflow, and hence water availability, may change in a future warmer world.

This study investigates the relationship between stream properties and quality of mixing in a multi-inlet vortex mixer (MIVM). While the determination of the Reynolds number is unambiguous for systems with a single velocity and length scale, the appropriate definition is not obvious for systems with multiple inlets, velocities, and dimensions such as the MIVM. Regression modeling on data from previous MIVM research was used to develop an optimal formulation for defining the Reynolds number for two-inlet and four-inlet mixers. Incorporation of volumetric weighting factors in the description of the Reynolds number improves the quality of the correlation between mixing effectiveness as measured by competitive reactions and stream flow rates.

We performed an error budget (i.e., error breakdown) analysis of hydrologic models to understand how error in rainfall accumulated as it propagated from input (rainfall) to various outputs. The analysis was performed with a “forensic” mindset in order to trace the error in each output variable to the error in the input source. Towards that end, we hypothesized that error in rainfall input is a conservable quantity for hydrologic models that honor the principle of conservation of mass. We focused on two types of errors—systematic error and random error—and four hydrologic models of varying levels of complexity. Systematic error and random error in input were found to be insensitive to the relative accumulation of error in the simulation of stream flow and evapotranspiration (ET) for the simplest statistical model. As systematic error increased in rainfall, error accumulated relatively more in stream flow for a linear storage-discharge model, while the proportion of error in ET decreased. This increase was ...

The regulation of rivers by dams, diversions, and reservoirs leads to perturbed streamflow time series, making it difficult for hydrological studies to assess natural trends and variability in runoff. This case study applies a variation of Hirsch’s maintenance of variance extension (MOVE) method to reconstruct La Grande Riviere’s 1979-2004 natural streamflow. The 1960-2004 hydrometric data for the Eastmain River and Grande Riviere de la Baleine are summed and compared with the 1960-1978 pre-regulated runoff time series of La Grande Riviere. Statistical analyses reveal a reasonable Nash-Sutcliffe efficiency (NSE) index (Ef = 0.58) and near 1:1 ratio between the standardized anomalies of the two river combination and La Grande Riviere’s 1960-1978 natural flow records. The accuracy of the proposed method is confirmed by the low error rates and a reasonably high NSE index (Ef = 0.64) exhibited between La Grande Riviere’s 1960-1978 observed and reconstructed monthly streamflow time series. Moreover, the recons...

The Texas state water plan, updated every 5 years, contains 50-year water management strategies that may have direct and significant effects on streamflow. Yet because of the prior appropriation doctrine in Texas, accurately simulating future streamflow is very difficult with conventional hydrological models. Consideration of the cumulative effect of the 2007 State Water Plan's water management strategies on streamflow using Texas' Water Availability Models (WAMs) shows that those strategies would (1) generally reduce streamflow at basin outlets, although spatial and temporal effects vary within each river basin; and (2) impact average streamflow differently than dry flow.

Analysis of data, including historical documentation, survey and navigation charts, and aerial imagery, representing a time series of 1851–2008 for the Snowy River ocean entrance area (located in East Gippsland, Victoria, Australia) shows that much morphological change has occurred, including entrance channel migration along 8000 m of Holocene sandy barrier formation. Increasingly frequent episodes of Snowy River entrance channel closure to Bass Strait is apparent from reference to the 1981–2008 record. The deployment of GIS technology allows such long-term coastal zone change to be visualised and documented, and, to some extent, quantified. Explanations for this change relate primarily to altered stream flow regimes. Within the Snowy River catchment, hydrological processes have been irretrievably altered after the development of the Snowy Mountains Hydro-electricity Scheme (SMHS) from 1951, which currently appropriates the vast majority of annual discharge from the high rainfall and snowfall are...

Increasing demand for water resources in the Western United States has given rise to many conflicts and has increased the need for more accurate and timely water management decisions. Snow-Covered Area (SCA) is an important hydrologic variable for both volumetric and daily stream flow forecasting. Satellite data provide the ideal way to map snow cover in mountain regions; however, the utility of these datasets have been limited due to the large number of scenes that are contaminated with cloud cover. To improve the utility of these datasets for the snowmelt season, in particular the Moderate Resolution Imaging Spectroradiometer (MODIS) Daily Snow-Cover Product dataset, a new procedure was developed to predict snow-cover in cloud-obscured areas using a snow-occurrence map technique. Results show that this method effectively increases the usefulness of the MODIS Snow-Cover product in mapping the daily evolution of snow cover extent in the Big Lost River Basin located in southeastern Idaho.

This paper reports on a broad-scale assessment of water yield impacts of the 2003 Alpine bush fires which burnt over a million hectares across north-eastern Victoria and Southern NSW, including catchments of a number of key water storages such as Hume and Dartmouth Dams and also the Gippsland Lakes. A new model - Bushfire Impact on Stream flow Yield (BISY) - was developed to estimate the change in stream flow. Stream flow response curves were derived for the different species which were based upon recorded stream flows and transposed based upon the mean annual rainfall. The impact on stream flow was estimated for 12 catchments ranging in size from approximately 500 to 10,000 km . For each catchment an annual stream flow response curve was produced at the catchment outlet, as well as spatially explicit data sets showing change in stream flow across the catchment. The results were aggregated to estimate the total change in mean annual stream flow for the River Murray and Gippsland Lakes.

Access to daily streamflow data at the catchment scale, is a central component of many aspects of water resources and water quality management. However, the majority of river reaches in many catchments in Kenya are ungauged or poorly gauged, and in some cases existing measurement networks are declining. Long-term continuous monitoring is not being done due to high costs of equipment maintenance. Therefore, there is a need for an alternative tool such as a catchment-scale hydrological model that is capable of predicting the daily streamflow. An approach is presented of predicting daily streamflow using a physically-based catchment-scale model, the geospatial Stream Flow Model (SFM). The SFM was developed using the “C” programming language and the user interface was developed using the Avenue script of the ArcView software. The SFM simulates the dynamics of runoff processes by utilizing remotely sensed and widely available global or local data sets. The model was applied in the Masinga catchment, K...

Instream flow affects biophysical habitat for aquatic species and “angler habitat” or “fishability.” Previous work speculates about flows that provide fishability, but without detailed information or analyses. This article presents anglers' normative flow evaluations for fishability on segments of eight Pacific Northwest rivers. Results show varying evaluations across rivers, with optimal fishing flows ranging from 5 to 118% of mean annual flow, and evaluations appear to be influenced by type of river segment, target species, and angling technique. This suggests comprehensive assessments will require case-specific information rather than applications of “rule-of-thumb” formulae. Findings also highlight potential differences between flow requirements for “angler habitat” versus “fish habitat.” Variables likely to influence fishability evaluations include effects that anglers can assess in social science research and effects that require biophysical studies. Fisheries management requires consideration of th...

Design flood estimation in small to medium-sized ungauged catchments is frequently required in hydrological design and is of great economic significance. The currently recommended method in Australian Rainfall and Run-off for south-east Australia is the Probabilistic Rational Method, the central component of which is a run-off coefficient that is assumed to vary smoothly over the geographical space. This paper aims to develop an alternative method of design flood estimation in small to medium-sized ungauged catchments in south-east Australia based on a quantile regression technique. This uses stream flow and catchment characteristics data from 88 catchments in south-east Australia. The developed prediction equations satisfy the underlying model assumptions very well and include hydrologically meaningful predictor variables that are readily obtainable. An independent test indicates that these prediction equations can provide reasonably accurate design flood estimates in the study area for small to medium-sized ungauged catchments.

This paper reports on a number of advances in the hydrologic characterisation of farm dams that are required in the assessment of farm dam impacts on stream flows. While the characteristics were derived for input to the TEDI simulation model, the generic nature of the information derived is applicable to any quantitative analysis of farm dam impacts, regardless of the method used. The use of topographic maps and aerial photography to identify the number and volume of farm dams is discussed, and this includes development of a functional relationship between farm dam surface area and volume. An essential component required for the estimation of farm dam impacts is the proportion of a dam's volume used to satisfy demands, and this is investigated using a regional survey of landholders. Typical size distributions of farm dams used for irrigation, and for stock and domestic purposes are presented, as is information on the range of farm dam densities encountered across Victoria. Farm dam and catchment characteristics derived for 1600 Victorian catchments were used along with previously derived prediction equations to estimate the impacts of farm dams on a range of stream flow indices. The manner in which this regional information can be used to rapidly estimate the impacts of farm dams on specific catchments is also discussed and presented.

Farm dams play an important role in Australian agriculture. In most cases the impact of an individual farm dam is relatively small, though the cumulative impact of farm dams on stream flows can be significant. A simulation model, Tool for Estimating Dam Impacts (TEDI) has been developed with the specific intention of modelling the hydrologic effect of farm dams on downstream flows. The TEDI model has a conceptually simple structure that was developed to be commensurate with the coarse level of information that is generally available at the catchment scale. Given the simplicity of this model, it is desirable to investigate the salient assumptions to determine whether there are compelling scientific reasons to increase the level of modelling complexity. This paper describes the development and application of a detailed simulation model (called CHEAT) that was used to assess the efficacy of the simplifying assumptions used in TEDI. The CHEAT model was configured to exactly emulate TEDI, and enhancements were progressively introduced in order to simulate greater levels of hydrologic complexity. The impacts of different simplifying assumptions are assessed for three catchments, one in Victoria with low stream flow yields and a moderate density of farm dam development, and the other two are located in Victoria and South Australia, with high yields and high density of farm dam development. All three catchments are located in regions that typically support dry land farming. On the basis of the three catchments considered it is tentatively concluded that the combined effect of the simplifying assumptions in the TEDI model have a small influence on the results, and that it can be used a practical tool for the estimation of farm dam impacts.

Based on the analysis of the three-year (2000–2002) monitoring data of the four times intermittent stream water conveyance to the lower reaches of Tarim River where the stream flow was dried up for more than 30 years and the measurement of PRO, SOD and POD in plants collected from 24 vegetation plots, it is concluded that the stream water conveyance plays an important role in lifting groundwater level. The groundwater nearby the watercourse was raised from 5–8 m in depth before the stream water conveyance to 2.5–5 m after stream water conveyance. The physiological response of Phragmites communis, Tamarix spp. and Populus euphratica to the change of groundwater is sensitive and represents a grads change obviously. The growth of the plants in the lower reaches of Tarim River is stressed by drought to various degrees. Lengthways, the drought stress exposed to the plants increases with groundwater depth from the upper sections to the lower sections; and breadthwise, the drought stress exposed to the ...

Field trips are essential for learning geoscience, but can be logistically challenging for introductory-level courses with large enrollments. Transporting large numbers of undergraduate students to roadway or stream bank exposures can be time consuming, expensive, and unsafe. To address this problem, the author designed three campus-based field exercises for an introductory geoscience course. Students collected and analyzed data from campus features to learn about rock weathering, retaining wall stability, and stream flow. They preferred outdoor campus exercises over indoor exercises, because they were more realistic, interesting, and interactive. The outdoor exercises utilized features common to many college campuses and thus could easily be implemented elsewhere. While the campus exercises do not replace a need for conventional road trips in upper-level courses, they are an effective way to introduce fieldwork in large introductory-level courses.

In southwestern Australia, the prediction of land salinity and stream flow trends requires the accurate construction of groundwater surfaces. This information is essential in the determination of groundwater and solute gradients. Airborne electromagnetic (AEM) data have the potential to be a useful tool in providing a `snapshot' of current regolith salt content and possible gradient directions. The focus of major previous research on groundwater and solute movement has been on linear breaks in electrical conductivity produced by dykes and faults. Interpreting electrical conductivity information within granitic regolith, with respect to groundwater recharge and salt mobility has, to a large extent, been ignored. Comparisons of the granitic regolith salt content and electrical conductivity measurement at Broomehill show that two types of regolith salt profile dominate. These profiles show marked differences in mineralogy and chloride content, and interpreted hydraulic properties. Unfortunately they are not readily distinguished in inverted AEM data for the area, making predictions of regolith salt content problematic. If AEM data are to be used in quantifying salt exported from catchments, then their interpretation should proceed with an appreciation of regolith heterogeneity and models of groundwater flow.

Theoretical and experimental investigations are presented on the threshold of noncohesive sediment motion under a steady-uniform stream flow on a combined transverse (across the flow direction) and longitudinal (streamwise direction) sloping bed. Theoretical analysis of the equilibrium of a sediment particle lying on a combined transverse and longitudinal sloping bed shows that the critical shear stress ratio (ratio of critical shear stress for a sloping bed to that for a horizontal bed) is a function of the transverse bed slope, longitudinal bed slope, angle-of-repose of sediment particles and lift-drag ratio. As in laboratory flume study, the uniform flow is difficult to establish in a steeply sloping channel and is impossible to obtain in an adversely sloping channel, experiments were conducted in two inverted semicircular ducts (closed-conduit flow) for three sizes of uniform sediments. The critical shear stresses for experimental runs were determined considering side-wall correction. The experimental...

A salt and water balance model was developed to represent stream flow and salinity generation processes following land use changes. At first a fundamental building-block model was developed based on the 'downward approach'. The building-block model was tested and validated with data from six experimental sub-catchments within the Collie River basin in Western Australia. The approach requires specification of five physically meaningful key parameters, most of which can be obtained a priori or easily calibrated. Stream flow and salinity from the Collie River catchment, with an area of 2,545 km2, has increased significantly due to clearing of 26% of the area during 1940-70s. For this study the catchment was divided into 91 sub-catchments and the building-block model was applied to each of the sub catchments. Most of the known catchment attributes such as stream length, average slope, soil type, profile thickness and salt storage were incorporated into the model. Parameter values obtained from experimental sub-catchments were appropriate for representing the daily stream flow generation processes of the whole catchment. However, the prediction of stream salinity and salt loads was improved by running the model a number of times and taking the final values of the transient stream zone stores as an initial condition. The modelled daily stream flow, salinity and salt load hydro graphs matched very well for all gauged sub-catchments.

Small-scale irrigation “Fadama” plays a key role in the economics of Nigeria as a basic source of food, income, and employment, especially for women in the “slack” period of rainfed agriculture. A study was undertaken to assess the practice of Fadama irrigation in Oyo and Osun states of Nigeria with a view to better understand the characteristic problems and needs. This paper reports on some general information on Fadama irrigation that are useful to project planners and assisting agencies. Fadama irrigation practice has increased significantly over the last 10 years because of increasing demand and high cost of vegetables produced by farmers. The majority of farmers are assisted by World Bank funded States Agricultural Development Program (ADP) through the provision of pumps and irrigation infrastructure. Farmers lack adequate start up capital and are frequently faced with irregular fuel supply, frequent pump breakdown, low stream flow, and well dry ups. Those using the furrow system also complained of h...

The influence of large woody debris (LWD) on channel morphology was assessed in five pine plantation and five native forest streams in the Nelson region of New Zealand. LWD volumes averaged 127 m3 ha–1 in pine plantation streams and 94 m3 ha–1 in native forest streams. Most of the LWD in pine and native streams had no influence on channel morphology (78 and 54%, respectively). Those LWD pieces influencing channel morphology contributed mainly to sediment storage in both pine and native streams as well as flow deflection and debris collection in the native streams. Wood aligned either perpendicular or obliquely to stream flow and positioned on or partly buried in the stream bed had the greatest influence on channel morphology. There were twice as many pools in native streams as in pine streams, and scour processes formed the majority of pools. LWD influenced c. 50% of pool formation in both pine and native streams and increased pool variety. LWD volumes in these streams are low compared with Pacif...

The group approach that treats hydrological data as groups rather than as single-valued observations was proposed in a companion paper. Various models representing four techniques are briefly presented and applied to single series and bi- series cases, respectively, in this paper. The techniques represented by these models are regression, time series analysis, partitioning modelling, and artificial neural networks. The utility of the models for estimating missing streamflow data using the group approach is investigated. It turns out that the group approach is valid for estimating missing values, and possibly other applications, when data are significantly auto-correlated. L'estimation de groupe pour l'estimation des donnees hydrologiques manquantes: II. Application aux debits Resume L'approche de groupe, traitant les donnees hydrologiques comme des suites de groupes plutot que comme des suites d'observations singulieres a ete presentee dans un papier preliminaire. Divers modeles utilisant quatre techniques differentes sont brievement presentes et ont ete appliques aux cas de series simples ou doubles. Ces techniques sont la regression, l'analyse de series chronologiques, la segmentation et les reseaux de neurones artificiels. L'utilite de ces modeles pour estimer les donnees de debit manquantes en utilisant l'approche de groupe a ete examinee. Il apparait que l'approche de groupe est appropriee pour estimer les valeurs manquantes, et probablement pour d'autres applications, quand les donnees sont significativement autocorrelees.

We have used a variety of approaches to introduce quantitative concepts into our introductory geology classes, some of which rely on using case studies of local rivers to improve student interest and appreciation of quantitative methods in scientific problem solving. Fortunately, there are rivers in most parts of the country, so these approaches are easily transferable and applicable in many areas. A simplified form of the continuity equation applied to stream flow serves as the starting point for developing a discussion of how and why local rivers are channelized for flood control. Students also analyze the recurrence interval of flooding along a local river of interest.

The associations between mean annual stream flow records from 15 rivers draining the Argentine Andes, ranging from the Altiplano to Patagonia, and the Southern Oscillation Index (SOI), as established through simple lag cross-correlation, are examined. The results indicate that rivers in the Cuyo region (30° to 40°S) are negatively associated with the SOI but that the response is lagged by about one year through the regional winter maximum of precipitation and subsequent snowmelt. Stream flow in the area also has a strong positive association with winter precipitation totals in Central Chile. A statistical analysis of recent synoptic variability indicates that the difference between regional zonal and meridional flow patterns is responsible for observed fluctuations of winter precipitation. This is in keeping with the general observation of greater meridional activity globally during warm phases of El Nino-Southern Oscillation (ENSO), and a dominance of zonal flows during cold phases. Both regional stream ...

Three approaches to modelling the duration of streamflow droughts at eight southern African sites are considered; a non-parametric method (that of Kaplan-Meier) is compared with the fitting of two simple parametric models: the exponential and Weibull. All techniques allow the instantaneous probability of a drought coming to an end to differ between wet and dry seasons, using the concept of censored data. Model-fitting is discussed, and the Kaplan-Meier estimates permit an assessment of the fit of the parametric models, with the aim of finding a parsimonious model for the data, which can be used for predictive purposes. In most cases considered herein, either the exponential or Weibull approach is found to be adequate.