Off-stream Water Research Articles

Geomembrane factory and field thermally welded seams comparison

This technical paper presents a unique comparison of geomembrane factory and field welded thermal seams for a large off-stream water reservoir project. The results of the comparison show that factory welded seams exhibit higher seam peel and shear strengths at yield, less variability, and more consistency than field welded thermal seams. In particular, the results show that factory seams are about 10% stronger than field seams in shear and about 9% stronger in peel strength at yield. More importantly, this resulted in 100% of the factory welded seams passing the project seam strength requirements even though the factory welding speed was 1.1–1.6 times faster than the field welding speed. Conversely, about 25% of the field welded seams did not pass the initial specified field seam shear strength requirement, which caused significant delays, scheduling, and other construction issues. As a result, the field seam shear strength requirement was reduced from 9.6 kN/m to 8.2 kN/m to increase the number of field seams that achieved project requirements. Because the geomembrane was primarily factory fabricated, there were about 78% less field seams on this project than if the geomembrane was entirely field fabricated.

Shifting from volume to economic value in virtual water allocation problems: A proposed new framework and methodology

PurposeThe water footprint provided a full methodology to operationalise the virtual water concept (the volume of water used along a supply chain to produce products and services). A key theme in the water footprint literature is the efficient allocation of water resources at the global scale given the feasibility of trading water intensive commodities from water rich to water poor areas: this is an economic problem of resource allocation between alternative and competing demands, albeit with a novel international component. Moreover, given that price signals indicating relative scarcity are usually either absent or distorted for water, it is also a problem that can be seen through the lens of environmental (or non-market) valuation. However, to date environmental valuation has not been used to inform the efficient use and allocation of water within and between the different locations encompassed by international supply chains. MethodsDrawing on an agri-food supply chain framework that we propose in this paper, we begin by conceptualising the economic values that accrue to water consumption (blue and green water) and degradation (grey water) at different points along a supply chain. Based on this conceptualisation, we assess the extent to which it is possible to approximate these economic values by relying on existing secondary data on the shadow value of water in different contexts. The use of secondary data in this way is known as benefit (or value) transfer. To achieve this, 706 unit estimates of the economic value of water are collected, standardised and reviewed encompassing off-stream water applications (agriculture, industry and municipal) and in-stream ecosystem services (waste assimilation, wildlife habitat, recreation, hydrological functions and passive uses). From this, a proposed methodology for valuing virtual water is presented and illustrated using the case study of global durum wheat pasta production. ResultsThe case study shows the total value of the virtual water used to produce one tonne of durum wheat pasta ($212). More importantly, the case study also highlights how variations in economic value between multiple locations where durum wheat is cultivated (Saskatchewan $0.10 m3, Arizona $0.08 m3 and Baja California $0.24 m3) indicate relative water scarcity and thus impact, as well as the potential for a more efficient allocation of virtual water. ConclusionsThe main conclusion from this research is that when geographical disparities in the economic value of water use within a supply chain are accounted for, what was perhaps considered sustainable in volume terms, might not, in fact, represent the optimal allocation. However, future research opportunities highlight the need for additional data collection on the economic value of water in several contexts. This additional data would help the environmental valuation community to undertake a more comprehensive and robust approach to virtual water valuation.This paper is accompanied by the Data in Brief article entitled “Dataset on the in-stream and off-stream economic value of water.”

Environmental factors influencing cattle's water consumption at offstream watering points in rangeland beef cattle

Agricultural best management practices (BMP) are of global importance to protect and promote sustainable food supplies and natural resources. Providing an offstream watering point (OSWP) is a functional and cost-effective BMP recommended to assist in maintaining or improving riparian areas and instream water quality. Understanding which factors contribute to cattle's use of OSWPs may enhance the decision making process for graziers when they consider implementing the use of an OSWP. This study's objective were to understand how cattle utilise OSWPs where they have access to an OSWP as the only drinking source compared to where a choice exists between drinking from an OSWP and a river. Choices were determined across a range of environmental factors, including water quality represented by total dissolved solids, climatic factors such as temperature humidity index, the number of rainfall days and wind speed, OSWP distance to stream, stocking density and vegetation greenness within 100 m from the OSWP. The results indicated that 1) cattle consume approximately half of their daily water from the OSWP when they have access to both an OSWP and the river (p = 0.023), with the number of rainfall days being a significant contributing factor (p = 0.037) with cattle consuming less water from OSWP during rain events and 2) Rainfall events influence WC consumption at OSWPs which may alter both vegetation and OSWP water quality and in turn influence how cattle select for water sources, but how cattle select for water sources will need of further researched. Furthermore, vegetation greenness around OSWPs may be of less importance where cattle have river access.

Influence of off-stream watering systems on cattle behaviour adjacent to Lower Little Bow River in Southern Alberta

Off-stream waterers (OSWs) located in upland pastures may be effective in reducing livestock impacts on riparian areas and rivers, but little research has been conducted on the impact of OSWs located closer to rivers. We studied cattle behaviour over four years (2012–2015) for a portable OSW at two sites (18–25 m from river) along an unfenced reach, and two permanent OSWs (41–68 m from river) located adjacent to the fenced reach with restricted cattle-access along the Lower Little Bow River in southern Alberta. The number of cattle drinking from the OSW versus river or restricted access site, as well as number of cattle on the bench-terrace or riparian zone with and without OSW, was determined. Significantly (P ≤ 0.10) greater (15-fold) number of cattle per day preferred to drink from the OSW compared to the river at the first location (Site 1) along the unfenced reach in June of 2012, but there was no significant difference at the second location (Site 2) along this same reach in July–August of 2012. Significantly greater (1.7–3.4 fold) numbers of cattle were present on the bench-terrace than the riparian zone when the OSW was present along the unfenced reach. Similar number of cattle preferred to drink from the OSW and restricted river-access site along the south side of the fenced reach in 2013 and 2015, and greater (2.7 fold) number preferred to drink from the river than OSW in 2014. In contrast, the permanent OSW on the north side of the fenced reach had significantly more (2.7 fold) cattle preferring to drink from the OSW than river-access site in 2015. Our results generally supported the hypothesis that OSWs located closer (≤68 m) to rivers were effective, but there were some exceptions.

Scarcity of fresh water resources in the Ganges Delta of Bangladesh

Understanding the interdependency, availability, and accessibility of surface water and groundwater plays a major role in identifying and managing water security. The Ganges Delta in Bangladesh is a classic example of a water insecurity scenario in a transboundary river basin where concerns in quantity, quality, and timing of available water are producing disastrous conditions. This study examines surface water and groundwater uses and demands, seasonal availability, sustainability, and potential water security concerns. Human interventions that can influence seasonal water availability and shifting demands between surface water and groundwater are also examined. Surface water availability was analyzed using streamflow including the effects of upstream water diversions, rainfall, temperature, and evapotranspiration. Groundwater data was collected from 283 locations established by the Bangladesh Water Development Board. Total water storage anomaly data from the GRACE satellite (2002–2016) was analyzed to assess changes in groundwater availability. Both in situ and GRACE data show a significant declining trend in groundwater. Comparisons of groundwater recharge and withdrawal amounts in six different years (1983, 2009–2012, 2015) indicate an unsustainable water withdrawal condition. Irrigation is the largest sector of off-stream water use with total water withdrawal amounting to 31% for surface water and 68% for groundwater. The region’s domestic water use entirely depends on groundwater, which is problematic due to arsenic pollution. This study provides insight into the changes in surface water and groundwater resources and limitations to freshwater availability, thereby encouraging a better management strategy for water resources in the region.

Cattle use of off-stream water developments across a northeastern Oregon landscape

Water developments have been considered a fundamental tool for dispersing livestock and reducing livestock impact on riparian and aquatic habitats associated with perennial streams. Quantifying the efficacy of water developments has been difficult because of the need to continuously monitor water sources for the timing and intensity of use. The advent of global positioning system (GPS) tracking technology has largely overcome this hurdle and presented new research opportunities. We conducted a five-year study to quantify and evaluate the relative use of existing water developments by cattle on three extensive study areas in northeastern Oregon, United States. Ten randomly selected beef cows from herds grazing each study area were fitted with GPS collars recording animal positions at five-minute intervals throughout the grazing season. Cattle occupancy in 60 m (196.9 ft) buffers around water developments was determined monthly and annually. Use of water developments was contrasted with that of riparian zones. Cattle use of water developments varied substantially from site-to-site, month-to-month, and year-to-year. In some months, cattle watered exclusively from off-stream developments, and in others, cattle watered nearly exclusively from streams. Substantial differences in the relative use of individual water developments were also seen by season and year. Some developments received no use at all during the five-year study while others were visited frequently. Our results suggest off-stream water development is a useful managerial strategy, but careful placement is required to improve the likelihood that cattle will find and use these water sources and thus decrease their dependence and use of permanent streams and associated riparian areas.

Pasture BMP effectiveness using an HRU-based subarea approach in SWAT

Many conservation programs have been established to motivate producers to adopt best management practices (BMP) to minimize pasture runoff and nutrient loads, but a process is needed to assess BMP effectiveness to help target implementation efforts. A study was conducted to develop and demonstrate a method to evaluate water-quality impacts and the effectiveness of two widely used BMPs on a livestock pasture: off-stream watering site and stream fencing. The Soil and Water Assessment Tool (SWAT) model was built for the Pottawatomie Creek Watershed in eastern Kansas, independently calibrated at the watershed outlet for streamflow and at a pasture site for nutrients and sediment runoff, and also employed to simulate pollutant loads in a synthetic pasture. The pasture was divided into several subareas including stream, riparian zone, and two grazing zones. Five scenarios applied to both a synthetic pasture and a whole watershed were simulated to assess various combinations of widely used pasture BMPs: (1) baseline conditions with an open stream access, (2) an off-stream watering site installed in individual subareas in the pasture, and (3) stream or riparian zone fencing with an off-stream watering site. Results indicated that pollutant loads increase with increasing stocking rates whereas off-stream watering site and/or stream fencing reduce time cattle spend in the stream and nutrient loads. These two BMPs lowered organic P and N loads by more than 59% and nitrate loads by 19%, but TSS and sediment-attached P loads remained practically unchanged. An effectiveness index (EI) quantified impacts from the various combinations of off-stream watering sites and fencing in all scenarios. Stream bank contribution to pollutant loads was not accounted in the methodology due to limitations of the SWAT model, but can be incorporated in the approach if an amount of bank soil loss is known for various stocking rates. The proposed methodology provides an adaptable framework for pasture BMP assessment and was utilized to represent a consistent, defensible process to quantify the effectiveness of BMP proposals in a BMP auction in eastern Kansas.

Off-Stream Watering Systems and Partial Barriers as a Strategy to Maximize Cattle Production and Minimize Time Spent in the Riparian Area.

Simple SummaryThe implementation of off-stream waterers (OSW) may reduce the amount of time cattle spend in riparian areas, thus minimizing impacts such as removal of vegetation, soil compaction, and deterioration in water quality. Furthermore, when used with natural barriers as a partial exclusion method, these management strategies may offer a cost-effective alternative to completely excluding cattle via streambank fencing. This study was conducted to determine the impact of OSW and barriers on animal performance and watering behavior. The presence of OSW had no significant effect on cow and calf weights averaged over the grazing season. Although the results were not consistent over the periods and locations, the data provided some indication of the efficacy of the natural barriers on deterring cattle from the riparian area. Cattle watered at the OSW when available, but they did not use the OSW exclusively. The observed inconsistency may, in part, be attributed to the environmental conditions present during this field trial.A study was conducted in 2009 at two locations in Manitoba (Killarney and Souris), Canada to determine the impact of off-stream waterers (OSW) with or without natural barriers on (i) amount of time cattle spent in the 10 m buffer created within the riparian area, referred to as the riparian polygon (RP), (ii) watering location (OSW or stream), and (iii) animal performance measured as weight gain. This study was divided into three 28-day periods over the grazing season. At each location, the pasture—which ranged from 21.0 ha to 39.2 ha in size—was divided into three treatments: no OSW nor barriers (1CONT), OSW with barriers along the stream bank to deter cattle from watering at the stream (2BARR), and OSW without barriers (3NOBARR). Cattle in 2BARR spent less time in the RP in Periods 1 (p = 0.0002), 2 (p = 0.1116), and 3 (p < 0.0001) at the Killarney site compared to cattle in 3NOBARR at the same site. Cattle in 2BARR at the Souris site spent more time in the RP in Period 1 (p < 0.0001) and less time in Period 2 (p = 0.0002) compared to cattle in 3NOBARR. Cattle did use the OSW, but not exclusively, as watering at the stream was still observed. The observed inconsistency in the effectiveness of the natural barriers on deterring cattle from the riparian area between periods and locations may be partly attributable to the environmental conditions present during this field trial as well as difference in pasture size and the ability of the established barriers to deter cattle from using the stream as a water source. Treatment had no significant effect (p > 0.05) on cow and calf weights averaged over the summer period. These results indicate that the presence of an OSW does not create significant differences in animal performance when used in extensive pasture scenarios such as those studied within the present study. Whereas the barriers did not consistently discourage watering at the stream, the results provide some indication of the efficacy of the OSW as well as the natural barriers on deterring cattle from the riparian area.

Study on Off-Stream Ecological Water Demand of Fu River Basin

According to researches on mechanism and concept of off-stream ecological water demand, off-stream ecological water demand of Fu River Basin is consist of ecological water demand for soil and water conservation and for urban public green space, considering the current situation and planning objectives of off-stream ecological water demand of Fu River Basin. Directly calculation method is employed in this study. Choosing 2005 as the current year in this study, indicators of public green space and soil erosion data are obtained. Then the ecological water demand of urban public green space in Fuzhou City is determined as 0.438×108m3 and the water demand for off-stream soil and water conservation in Fu River Basin is determined as 0.3159×108m3 in virtue of quota method. The off-stream ecological water demand in the Basin (2005 as the current year) is about 0.359×108m3. The determination of the off-stream ecological water demand in the basin provide a scientific basis on taking a variety of water-saving measures, improving the recovery rate of sewage treatment and increasing the off-stream ecological water consumption. Results of this study will make the ecological environment of this area to achieve a healthy state, and shall greatly improve regional water resources and water environmental situation.

Pasture size effects on the ability of off-stream water or restricted stream access to alter the spatial/temporal distribution of grazing beef cows.

For 2 grazing seasons, effects of pasture size, stream access, and off-stream water on cow distribution relative to a stream were evaluated in six 12.1-ha cool-season grass pastures. Two pasture sizes (small [4.0 ha] and large [12.1 ha]) with 3 management treatments (unrestricted stream access without off-stream water [U], unrestricted stream access with off-stream water [UW], and stream access restricted to a stabilized stream crossing [R]) were alternated between pasture sizes every 2 wk for 5 consecutive 4-wk intervals in each grazing season. Small and large pastures were stocked with 5 and 15 August-calving cows from mid May through mid October. At 10-min intervals, cow location was determined with Global Positioning System collars fitted on 2 to 3 cows in each pasture and identified when observed in the stream (0-10 m from the stream) or riparian (0-33 m from the stream) zones and ambient temperature was recorded with on-site weather stations. Over all intervals, cows were observed more (P ≤ 0.01) frequently in the stream and riparian zones of small than large pastures regardless of management treatment. Cows in R pastures had 24 and 8% less (P < 0.01) observations in the stream and riparian zones than U or UW pastures regardless of pasture size. Off-stream water had little effect on the presence of cows in or near pasture streams regardless of pasture size. In 2011, the probability of cow presence in the stream and riparian zones increased at greater (P < 0.04) rates as ambient temperature increased in U and UW pastures than in 2010. As ambient temperature increased, the probability of cow presence in the stream and riparian zones increased at greater (P < 0.01) rates in small than large pastures. Across pasture sizes, the probability of cow presence in the stream and riparian zone increased less (P < 0.01) with increasing ambient temperatures in R than U and UW pastures. Rates of increase in the probability of cow presence in shade (within 10 m of tree drip lines) in the total pasture with increasing temperatures did not differ between treatments. However, probability of cow presence in riparian shade increased at greater (P < 0.01) rates in small than large pastures. Pasture size was a major factor affecting congregation of cows in or near pasture streams with unrestricted access.

Detecting the Influence of Best Management Practices on Vegetation Near Ephemeral Streams With Landsat Data

Various best management practices (BMPs) have been implemented on rangelands with the goals of controlling nonpoint source pollution, reducing the impact of livestock in ecologically important riparian areas, and improving grazing distribution. Providing off-stream water sources to livestock in pastures, cross-fencing, and rotational grazing are common rangeland BMPs that have demonstrated success in drawing livestock grazing pressure away from streams. We evaluated the effects of rangeland BMP implementation with six commercial-scale pastures in the northern mixed-grass prairie. Four pastures received a BMP suite consisting of off-stream water, cross-fencing, and deferred-rotation grazing, and two pastures did not receive BMPs. We hypothesized that the BMPs increased the quantity of riparian vegetation cover relative to the conditions in these pastures during the pre-BMP period and to the two pastures that did not receive BMPs. We used a series of 30-m Landsat normalized difference vegetation index (NDVI) images to track the spatial and temporal changes (1984–2010, n = 24) in vegetation cover, to which NDVI has been well correlated. Validation indicated that the remotely sensed signal from in-channel vegetation was representative of ground conditions. The BMP suite was associated with a 15% increase in the in-channel NDVI (0–30 m from stream centerline) and 18% increase in the riparian NDVI (30–180 m from stream center line). Conversely, the in-channel and riparian NDVI of non-BMP pastures declined 30% and 18% over the study period. The majority of change occurred within 2 yr of BMP implementation. The patterns of in-channel NDVI among pastures suggested that BMP implementation likely altered grazing distribution by decreasing the preferential use of riparian and in-channel areas. We demonstrated that satellite imagery time series are useful in retrospectively evaluating the efficacy of conservation practices, providing critical information to guide adaptive management and decision makers.

Can off-river water and shade provision reduce cattle intrusion into drinking water catchment riparian zones?

Cattle defecation into rivers and overgrazing of riparian zones, are major concerns for drinking water catchment managers. Behaviour modification has been proposed instead of fencing for managing impacts, but reported success varies. Our study aimed to resolve whether provision of off-stream water and shade on real working farms could reduce the likelihood of cattle entering watercourses feeding Sydney, Australia's primary water supply, Lake Burragorang (34°S, 150°E). Cattle herds (1.4 and 11 Animal Unitsha−1) at two sites were fitted with Global Positioning System (GPS) collars (n=12). Cattle movements were tracked following installation of industry-recommended off-stream water and shade (twelve 2 week duration control+treatment experiments). Some statistically significant differences in movement (Mann–Whitney U Prob.<0.0001) were observed, as judged by comparisons of riparian, water trough and shade NEAR distances, and riparian zone visit number, duration and frequency. But effect magnitudes were small, inconsistent between different experiments, and insufficient to justify widespread water and shade provision. These findings contrast with the marked reductions in riparian impacts reported for rangeland pastured (>≈1km2) cattle, but were not inconsistent with smaller scale grazing studies. Statistically significant correlations (Spearman R) were, however, observed (Goulburn_1, Robertson_2 experiments respectively) between the movement of cattle within the same herd (0.94, 0.85), cattle in adjacent fields (0.7, 0.64), and heat stress related factors (temperature, light, humidity, wind) (0.1–0.5) indicating GPS tracking was sound and other factors more strongly influenced animal location. We hypothesize that our off-stream water and shade did not markedly influence cattle movement because our paddocks were relatively small (1.5 and 20ha) compared to rangeland pastures. The study's main limitation was that GPS error prevented differentiation of riparian zone interaction from full stream contact. We recommend in future using direct video to overcome this, and differential quantification of these impacts.

Evaluation of selected soil properties for indicating cattle activity at off-stream watering and river access sites in southern Alberta

Miller, J. J., Curtis, T. W., Bremer, E., Chanasyk, D. S. and Willms, W. D. 2013. Evaluation of selected soil properties for indicating cattle activity at off-stream watering and river access sites in southern Alberta. Can. J. Soil Sci. 93: 343–358. Off-stream watering troughs may reduce surface water pollution by shifting nutrient distribution from natural watering sites along the river to around artificial water troughs some distance from the river. The objective of our study was to evaluate the suitability of nine soil properties for assessing the impacts of cattle activity adjacent to eight watering sites. Nine surface (0–5 cm) soil properties were evaluated along four 100-m transects at the five off-stream water troughs and three river access sites along the Lower Little Bow River in southern Alberta over 4 yr (2007–2010). The properties included P (total P, soil test P or STP), N (total N, NO3-N, NH4-N), total C, total C:total N ratio (TC:TN), chloride (Cl), and soil bulk density. Soil test P was significantly (P≤0.05) enriched at 65% of site-year comparisons, followed by total C (63%), NO3-N (55%), total P and TC:TN (50%). This suggested that these soil properties were relatively good indicators of cattle activity at the majority (&gt;50%) of watering sites. Chloride was a valid indicator only in non-saline areas (100% of four non-saline sites). Total C and TC:TN ratios were not valid indicators in the calcareous soils at all sites because of possible confounding influence of inorganic C. Overall, we recommend Cl as an indicator of cattle activity at watering sites not affected by soil salinity and high natural Cl levels, and STP as the best overall indicator of cattle activity at off-stream watering sites and river access sites. Certain soil properties were also influenced by distance from watering site, stocking rate, precipitation, and age of water trough.

Effects of an off-stream watering facility on cattle behavior and instream E. coli levels

Excessive levels of fecal bacteria are the leading cause of water quality impairment in Texas, and livestock with direct access to water bodies are potentially a significant source of these bacteria. To help address this, the effect of providing alternative off-stream watering facilities to reduce manure, and thus bacterial, deposition in or near surface waters was evaluated from July 2007 to July 2009 in Clear Fork of Plum Creek in central Texas. An upstream-downstream, pre- and post-treatment monitoring design was used with off-stream water provided only during the second year of the study. Flow, Escherichia coli (E. coli) concentration, and turbidity were measured twice monthly. Cattle movements were tracked quarterly using global positioning system collars to assess the effect of providing alternative water on cattle behavior. Results showed that when alternative off-stream water was provided, the amount of time cattle spent in the creek was reduced 43%. As a result, direct deposition of E. coli into Clear Fork of Plum Creek was estimated to be reduced from 1.11 × 107 to 6.34 × 106 colony forming units per animal unit per day. Observed pre- and post-treatment instream E. coli loads suggested similar reductions; however, these reductions were not statistically significant. Citation: Wagner KL, Redmon LA, Gentry TJ, Harmel RD, Knight R, Jones CA, Foster JL. 2013. Effects of an off-stream watering facility on cattle behavior and instream E. coli levels. Texas Water Journal. 4(2):1-13. Available from: https://doi.org/10.21423/twj.v4i2.6460.

Optimal Placement of Off-Stream Water Sources for Ephemeral Stream Recovery

Uneven and/or inefficient livestock distribution is often a product of an inadequate number and distribution of watering points. Placement of off-stream water practices (OSWP) in pastures is a key consideration in rangeland management plans and is critical to achieving riparian recovery by improving grazing evenness, while improving livestock performance. Effective OSWP placement also minimizes the impacts of livestock use radiating from OSWP, known as the “piosphere.” The objective of this study was to provide land managers with recommendations for the optimum placement of OSWP. Specifically, we aimed to provide minimum offset distances of OSWP to streams and assess the effective range of OSWP using Normalized Difference Vegetation Index (NDVI) values, an indicator of live standing crop. NDVI values were determined from a time-series of Satellite Pour l'Observation de la Terre (SPOT) 20-m images of western South Dakota mixed-grass prairie. The NDVI values in ephemeral stream channels (in-channel) and uplands were extracted from pre- and post-OSWP images taken in 1989 and 2010, respectively. NDVI values were normalized to a reference imagine and subsequently by ecological site to produce nNDVI. Our results demonstrate a significant (P < 0.05) increase in the nNDVI values of in-channel vegetation within 1 250m of OSWP following their implementation. The area of piospheres (n = 9) increased with pasture size (R2 = 0.49, P = 0.05) and increased with average distance to OSWP in a pasture (R2 = 0.43, P = 0.07). Piospheric reduction in nNDVI was observed within 200m of OSWP, occasionally overlapping in-channel areas. The findings of this study suggest placement of OSWP 200 to 1 250m from streams to achieve optimal results. These results can be used to increase grazing efficiency by effectively placing OSWP and insure that piospheres do not overlap ecologically important in-channel areas.

Marginal benefit based optimal water allocation: case of Teesta River, Bangladesh

This article describes a hydrologic–economic optimization model for allocating available river flow between competing off- and in-stream demands, based on the marginal benefits (MBs) of sectoral water uses in a segment of the Teesta River in Bangladesh. Irrigation, capture fishery and navigation are the main direct water uses considered. The value of irrigation water was estimated using the residual imputation method. Losses in yield caused by lowered irrigation supply, resulting from reduced river flow, formed the basis for establishing the total and MB functions for off-stream river water use (irrigation). Total and MB functions for in-stream water use (capture fishery, navigation) were developed using field survey data of beneficiaries' income as a function of river flow. Analysis was enhanced by applying AQUARIUS, which allocates water between users to maximize consumer surplus based on MB functions. Model results show that in-stream uses could not compete with off-stream uses in the case of the Teesta, as substantial benefit was obtained from irrigation. Environmental flow to safeguard river health and in-stream use was considered to be a constraint in the optimization, which results in a sizeable reduction in irrigation benefit with a small increase in in-stream benefit. The necessary trade-offs between economic efficiency and environmental protection are depicted, providing insight into a justifiable water allocation strategy for the Teesta.

Detecting Channel Riparian Vegetation Response to Best-Management-Practices Implementation in Ephemeral Streams With the Use of Spot High-Resolution Visible Imagery

Heavily grazed riparian areas are commonly subject to channel incision, a lower water table, and reduced vegetation, resulting in sediment delivery above normal regimes. Riparian and in-channel vegetation functions as a roughness element and dissipates flow energy, maintaining stable channel geometry. Ash Creek, a tributary of the Bad River in western South Dakota contains a high proportion of incised channels, remnants of historically high grazing pressure. Best management practices (BMP), including off-stream watering sources and cross fencing, were implemented throughout the Bad River watershed during an Environmental Protection Agency (EPA) 319 effort to address high sediment loads. We monitored prairie cordgrass (Spartina pectinata Link) establishment within stream channels for 16 yr following BMP implementation. Photos were used to group stream reaches (n=103) subjectively into three classes; absent (estimated <5% cover; n=64), present (estimated 5–40% cover; n=23), and dense (estimated >40% cover; n=16) based on the relative amount of prairie cordgrass during 2010 assessments of ephemeral channels. Reaches containing drainage areas of 0.54 to 692 ha were delineated with the use of 2010 National Agriculture Imagery Program (NAIP) imagery. Normalized difference vegetation index (NDVI) values were extracted from 5 to 39 sample points proportional to reach length using a series of Satellite Pour l’Observation de la Terre (SPOT) satellite imagery. Normalized NDVI (nNDVI) of 2152 sample points were determined from pre- and post-BMP images. Mean nNDVI values for each reach ranged from 0.33 to 1.77. ANOVA revealed significant increase in nNDVI in locations classified as present prairie cordgrass cover following BMP implementation. Establishment of prairie cordgrass following BMP implementation was successfully detected remotely. Riparian vegetation such as prairie cordgrass adds channel roughness that reduces the flow energy responsible for channel degradation.

Evaluation of cattle bedding and grazing BMPs in an agricultural watershed in Alberta

This paper highlights the environmental impacts of implementing beneficial management practices to address cattle bedding and direct access to the creek in a study watershed in southern Alberta, Canada. Approximately 35 cow-calf pairs grazed 194 ha of grass forage and had direct access to the creek in the spring and summer. During winter, the cattle were fed adjacent to the creek at an old bedding site. The practice changes included off-stream watering, bedding site relocation and fencing for rotational grazing. The cost was $15,225 and 60 h of labour. Four years of data were used in a before-and-after experimental design to evaluate the practice changes. After two years of post-implementation monitoring, riparian assessments showed an increase in plant diversity, but no change in the percent cover of the riparian species Salix exigua and Juncus balitus and a decrease in Carex sp. (P < 0.05). Water quality monitoring showed a decrease in the difference between upstream and downstream concentrations of total phosphorus, total dissolved phosphorus, total nitrogen, organic nitrogen and Escherichia coli (P < 0.10). These results showed that improved environmental changes in riparian and water quality can be measured following the implementation of beneficial management practices for cattle bedding and grazing.

Environmental quality of Lower Little Bow River and riparian zone along an unfenced reach with off-stream watering

► We evaluated off-stream watering on riparian zone and river. ► Off-stream watering reduced cattle on the river bank and in river. ► The BMP improved riparian health and prevented river pollution by cattle. ► Certain vegetative properties were improved at the cattle access site. ► Rainfall simulation quality at cattle access site was not affected. The goal of beneficial management practices (BMPs) such as off-stream watering without fencing is to direct cattle away from rivers, improve the environmental quality of the riparian zone, and prevent or reduce river pollution. We conducted a four year (2005–2008) study on an unfenced 1.3 km reach of the Lower Little Bow (LLB) River in southern Alberta, Canada where three off-stream watering systems were installed 290 to ≥730 m from the river in August, 2005. Our hypothesis was that off-stream watering would reduce cattle activity at the river, improve riparian health, prevent river pollution by cattle, and improve the soil, vegetative, and rainfall simulation runoff variables at a cattle access site near the river. Off-stream watering did not significantly ( p > 0.10) reduce the median number of cattle on the river bank, in the river, or drinking from the river one year later. However, there was a reduction of 20% ( p = 0.15) for median number of cattle on the river bank and a 72% reduction ( p = 0.20) for cattle in the river. The BMP moderately improved the riparian health score from 60% (2005) to 65% (2007). Our spatial analysis (upstream–downstream) of base-flow during the post-BMP period (2006–2008) suggested that off-stream watering prevented river pollution by cattle for the majority of water quality variables measured. Canopy cover at the cattle access site near the river was significantly ( p ≤ 0.10) increased by 26–53% one and two years after the BMP. Two years after the BMP was implemented, total basal area, biomass, and mulch were significantly increased by 37–106%, while bare soil and NO 3 -N in surface soil were decreased by 38–89%, respectively. In contrast, other vegetative and soil properties were not significantly improved. Concentrations of the majority of N and P fractions in rainfall simulation runoff were not significantly reduced, and may be related to the high precipitation in the pre-BMP year of 2005. We accept the hypothesis that off-stream watering improved riparian health, prevented river pollution by cattle, and improved certain vegetative (canopy cover, total basal area, mulch, bare soil) and soil properties (soil NO 3 -N) near the river. However, we reject the hypothesis that off-stream watering improved other vegetation (live basal area) and soil properties (bulk density, NH 4 -N, total N and C), or improved rainfall simulation runoff quality near the river. Although we cannot statistically prove that the positive benefits of off-stream watering on certain environmental variables was due to reduced cattle activity, the non-significant reductions in cattle activity suggested this may be a possibility.

A common basis for analysis, evaluation and comparison of offstream water uses

Many analyses of water uses and their impacts on available resources fail to reflect the contribution of return flow to existing supply, misuse the term “efficiency”, and assume immediate savings by changes in irrigation. Sound resources management requires a method of analysis applicable to all classes of offstream water uses. Drawing on previous analysis, a Water Uses Assessment Equation is proposed: a methodology founded on the principle of rigorous water accounting. Examples of applications are provided together with misleading analyses and conclusions that might be avoided in the future through use of the equation.