Irrigation Dams Research Articles

Dam regulation and riverine food-web structure in a Mediterranean river

Flow regimes are a major driver of community composition and structure in riverine ecosystems, and flow regulation by dams often induces artificially-stable flow regimes downstream. This represents a major source of hydrological alteration, particularly in regions where biota is adapted to strong seasonal and interannual flow variability. We hypothesized that dam-induced hydrological stability should increase the availability of autochthonous resources at the base of the food web. This, in turn, should favour herbivorous over detritivorous strategies, increasing the diversity of primary consumers, and the food-web width and length. We tested this hypothesis by studying the longitudinal variation in food-web structure in a highly-seasonal Mediterranean river affected by an irrigation dam. We compared an unregulated reach to several reaches downstream of the dam. Hydrological and sedimentological stability increased downstream of the dam, and altered the type and quantity of available resources downstream, prompting a change from a detritus-based to an algae-based food web. The fraction of links between top and intermediate species also increased, and the food web became longer and wider at the intermediate trophic levels. Food-web structure did not recover 14km downstream of the dam, despite a partial restitution of the flow regime. Our results advance the notion that hydrologic alteration affects riverine food webs via additions/deletions of taxa and variation in the strength and distribution of food-web interactions. Thus, flow regulation by dams may not only impact individual facets of biodiversity, but also food-web level properties across river networks.

Distributional Effects of Agricultural Infrastructure in Developing Countries: Large Irrigation Dams and Drought Mitigation in Nigeria

Despite the past investments and continued interests in public infrastructure like large irrigation dams, there has been limited evidence for their effects on household level consumptions and agricultural production, and how these effects are spatially distributed, depending on the locations of households in relations to the dams. Using a panel household survey, information of the locations of large irrigation dams, drainage basins, and drought index, we assess how large irrigation dams benefit households' consumptions and agricultural production, mitigate the effects of drought, and how these effects are distributed across drainage basins in Nigeria. We classify households into dam-basins (basins that contain large irrigation dams), downstream basins (those located downstream of dams), and other non-dam basins. Multinomial inverse-probability weighting method, combined with difference-in-difference methods, construct appropriate counterfactual samples, through which the effects of large irrigation dams and their variations across drainage basins are identified. We find that large irrigation dams largely benefit the downstream basins, rather than dam-basins or other basins. Households in downstream basins, for whom suitable matches can be found in other types of basins, are less affected by the drought and enjoy relatively stable growth rates of real per capita income and food consumption, compared to what they would experience if they were in other types of basins. Such relative stability in incomes and food consumption in downstream basins, despite the droughts, are partly due to the stable food production that is enabled by the supply of irrigation waters from the dams in the event of drought. These findings are robust against the effects of drought on water supply to the dams, proxy of state level political factors, and drought timing. The findings have important policy implications. Drainage basins have only been recently estimated relatively accurately in countries like Nigeria, while most irrigation dams in Nigeria had already been built by the 1990s. Locations of the new construction or rehabilitation of irrigation dams in Nigeria should carefully consider not only the agroecological and socioeconomic conditions, and weather-risks like droughts in the drainage basins where dams are located, but also these conditions of downstream drainage basins.

English

At the dawn of the 21st Century, the goal of achieving poverty reduction became a global concern. Diverse livelihood public interventions such as the provision of community dams since then have been implemented in rural settings including Nadowli-Kaleo District of the Upper West Region, Ghana to promote food security through dry-season farming. However, the objectives of these interventions have not been realized. Rather, rural farmers engaged in irrigation farming have resorted to the initiation and utilization of private water systems prompting the examination of factors accounting for the choice of irrigation operations. A case research design was adapted in the conduct of the investigation. Five communities were selected as cases based on a set of criteria namely, the presence of an open-access dam and on-going private irrigation schemes. Factors accruing to the preference for private water systems to that of open-access community dams for irrigation included contamination of dam water by other users such as funeral undertakers, water vendors and fishermen, as well as drying up of dam water. Although irrigation engagement tremendously benefits irrigation operators and consumers through provision of fresh vegetables for household consumptions and income generation, irrigation operations are however saddled with the destruction of irrigation crops by animals, financial inadequacies and limited knowledge of farmers in irrigation agronomy. Measures proposed to propel the productive capacity of rural irrigation farmers comprise: creation of irrigation fund for farmers, entrepreneurship training in basic agronomic techniques in irrigation farming, giving awards to irrigation farmers on Farmers’ Day Celebrations, establishment of block irrigation systems, and proper management of existing community dams. Key words: Agriculture, rural irrigation, private initiatives, sustainable livelihoods, irrigation systems.

Laboratory investigation and field evaluation of loess improvement using nanoclay – A sustainable material for construction

Loess soils are aeolian deposits of primarily silt sized soil particles, which are often lightly cemented. The wind-blown depositional process of loess formation yields a relatively loose soil structure that is particularly sensitive to changes in hydro-mechanical loading conditions, and the silt particles that comprise loess deposits are often easily eroded by water or wind. The main irrigation channels of Gonbad dam, located in northeastern Iran, are constructed on loess deposits and have experienced significant cracking and other forms of damage that can be attributed to subsidence and erosion of the loess soil. This study investigates the potential for effective loess stabilization using nanoclay, an engineered nanomaterial, both in the laboratory and in the field at the Gonbad dam irrigation channel site. To evaluate the effects of nanoclay stabilization, varying fractions of nanoclay ranging from 0.2% to 3% by mass were added to the natural loess soil. In the laboratory, representative specimens were prepared and subjected to a variety of tests, including Atterberg limits, standard Proctor compaction, unconfined compressive strength, unconsolidated undrained triaxial compression, wetting-induced collapse, and pinhole dispersivity. Results from the laboratory tests revealed that the addition of nanoclay altered the plasticity, strength, and stiffness behavior of the specimens. Also, the dispersivity and relative wetting-induced collapse behavior of the natural loess were impacted by the addition of nanoclay. In-situ investigation was performed at a selected section of the irrigation channel, to explore the effectiveness of nanoclay for improving the loess soil. Results of this pilot field study indicated that loess soils that had been stabilized with 2% nanoclay showed notable improvement. The field and laboratory obtained results were observed to be in general agreement.

Sustainable or senseless? Global lessons from dam building

The steep decline in freshwater biodiversity is a major cause for concern. Over the same period there has been a sharp increase in dam construction, with more than 3000 dams planned or proposed by 2030. The benefits of dams for water supply, irrigation and energy production are noted, but in repeating the common mistakes (Seven Sins of Dam Building) dam development has resulted in massive negative social and environmental impacts. By learning from past mistakes and using the available tools and standards, governments, industry and financiers can reach more balanced and sustainable outcomes. This paper draws from World Wide Fund's hydropower expertise with particular emphasis on Latin America and hydropower dams.

English

In Myanmar, the government has made a vast investment in the construction of dams to improve crop productivity and to ensure socioeconomic development. This study explores the differential impacts, in terms of socioeconomic conditions, of these investments for paddy farmers in Yedashe Township, in the Bago region in the south-central part of Myanmar. A farm survey among 95 respondents is used to compare the situation before and after the construction of a dam. It is observed that after the installation of the dam, the farmers could practice double rice cropping enabling them to gain higher income. The impact of the dam project on the employment rate, paddy yields and incomes were measured using normalized vector equations. A positive effect on all these factors was observed. The incomes of the farmers increased by benefiting from higher crop productivity, more crops per year, and more benefits over variable costs. However, the return above variable cash costs (RAVCC) and the benefit over cost (BC) ratio of head-end users was significantly higher than that of middle-reach and tail-end users. Therefore, the study additionally explored the problems of unequal water access and farmer-oriented solutions to these problems. The lack of monitoring and management of the irrigation institutions was found to be a major constraint for the development of the irrigation sector. Therefore, efficient utilisation of irrigation water by water-users, and policies as well as investments in the development of irrigation infrastructure need to be emphasised. Key words: Irrigation dam, downscaled water users, disequilibrium, impact assessment.

Analisis Kriteria untuk Perencanaan Program Pemeliharaan Embung Irigasi (Studi Kasus : Embung Haliwen dan Haekrit Kabupaten Belu)

: The problem of irrigation dams (small farm reservoair) is functional degradation, characterized by reduced capacity of collected water, sedimentation, seepage, the growth of wild plants in the body of weir / dike, erosion, and some other problems. Therefore, good and sustainable maintenance is required. One of them by determining the right criteria as the basis for planning the maintenance program. The determination of this criterion is based on fact (filling questionnaire) and literature review which then tested the validity and reliability to determine the criteria to be used. Furthermore, the analysis of the various criteria stated valid and reliable. Criteria are determined based on validity, reliability and frequency distribution with the number of procession answers is very important and important> 50%. The results of the analysis indicate influential Criteria and subcriteria namely Structural Stability Criteria (sub criteria: Body Dam, Embung Pool, Spillway, Building Assistance, Water Distribution Network, Condition Value); Physical and Environmental Criteria (subcriteria of Changes in the Natural Span, Rainfall and Evapotranspiration, Soil Structure around Embung, Plague of Plague Around Embung); Financial Criteria / Eknomi (subcriteria of Agricultural Product Result, Economic Value of Emung, Investment Fund); Government Policy Criteria (subcriteria: Spatial Plan, Provision of Maintenance Budget, Water Management, Institutional / Organization Aspect); Socio-Cultural Criteria (subcriteria: Community Participation, Local Wisdom / Customary Law, and Tourism Development)

Modelling the Risk Posed by the Zebra Mussel Dreissena polymorpha: Italy as a Case Study.

Wegenerated a risk map to forecast the potential effects of the spreading of zebra mussels Dreissena polymorpha across the Italian territory. We assessed the invader's potential impact on rivers, lakes, watersheds and dams at a fine-grained scale and detected those more at risk that should be targeted with appropriate monitoring. We developed a MaxEnt model and employed weighted overlay analyses to detect the species' potential distribution and generate risk maps for Italy. D. polymorpha has a greater probability of occurring at low to medium altitudes in areas characterised by fluviatile deposits of major streams. Northern and central Italy appear more at risk. Some hydroelectric power dams are at high risk, while most dams for irrigation, drinkable water reservoirs and other dam types are at medium to low risk. The lakes and rivers reaches (representing likely expansion pathways) at medium-high or high risk mostly occur in northern and central Italy. We highlight the importance of modelling potential invasions on a country scale to achieve the sufficient resolution needed to develop appropriate monitoring plans and prevent the invader's harmful effects. Further high-resolution risk maps are needed for other regions partly or not yet colonisedby the zebra mussel.

Evaluation of Seasonal Autoregressive Integrated Moving Average Models for River Flow Forecasting

Reservoir operation policies cannot be functional in instant decision making without forecasting the future reservoir inflows. For forecasting inflows into reservoirs with only hydrological data is available like Koga irrigation dam, multivariate forecasting models cannot be used to generate accurate river flow information. As a result, an evaluation of univariate Seasonal Autoregressive Integrated Moving Average (SARIMA) models was done for forecasting monthly Koga River flow with Gnu Regression, Econometrics and Time-series Library (GRETL) software. The stationarity of historical river flow sequence was checked by Augmented Dickey-Fuller (ADF) unit root analysis. Then, seasonality was removed from the river flow time series by seasonal differencing. Using seasonally differenced correlogram characteristics various SARIMA models were identified and evaluated, their parameters were optimized and diagnostic checks of forecasts were performed using residual correlograms and Ljung-Box tests. Finally, based on minimum Akaike Information criteria, SARIMA (1, 0, 1) (3, 1, 3)12 model was selected for Koga River flow forecasting. The stationarity test of the forecasted values of this model has proved the similarity of forecast values and patterns with those of the historical ones. Thus, irrigation managers could use this model and forecast information for optimal irrigation planning and development of reservoir operation strategies in order to protect farmers and downstream environment from water shortages. Moreover, the use of stationarity test of forecast flow patterns is useful and applicable in selecting best forecast model during forecasting of any river flows.

Developing a Water Quality Index (WQI) for an Irrigation Dam.

Pollution levels have been increasing in water ecosystems worldwide. A water quality index (WQI) is an available tool to approximate the quality of water and facilitate the work of decision-makers by grouping and analyzing numerous parameters with a single numerical classification system. The objective of this study was to develop a WQI for a dam used for irrigation of about 5000 ha of agricultural land. The dam, La Vega, is located in Teuchitlan, Jalisco, Mexico. Seven sites were selected for water sampling and samples were collected in March, June, July, September, and December 2014 in an initial effort to develop a WQI for the dam. The WQI methodology, which was recommended by the Mexican National Water Commission (CNA), was used. The parameters employed to calculate the WQI were pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), total hardness (TH), alkalinity (Alk), total phosphorous (TP), Cl−, NO3, SO4, Ca, Mg, K, B, As, Cu, and Zn. No significant differences in WQI values were found among the seven sampling sites along the dam. However, seasonal differences in WQI were noted. In March and June, water quality was categorized as poor. By July and September, water quality was classified as medium to good. Quality then decreased, and by December water quality was classified as medium to poor. In conclusion, water treatment must be applied before waters from La Vega dam reservoir can be used for irrigation or other purposes. It is recommended that the water quality at La Vega dam is continually monitored for several years in order to confirm the findings of this short-term study.

Perception of irrigation farmers’ livelihood on a changing climate in the Upper West region of Ghana

Agriculture in the Upper West region is primarily subsistence and rain-fed, and irrigation practice is significantly furrow andthe use of traditional watering can. This historical approach to agriculture is predicted to suffer severe setbacks due to climatechange. This research therefore explores farmers’ perception of climate change and its impact and how the farmers can cope withthe changing climate. The primary data was gathered through field observation, interviews and administration of questionnairesto about 400 irrigation farmers in three districts of the Upper West region. The data was analysed using 1. Statistical Packagefor Social Sciences (SPSS) and basic statistical tools. It was discovered that 62% of the farmers had no formal education withmajority above 50 years of age. Over 80% have observed rising temperatures and declining rainfall over the last few decades.This has led to higher evaporation and siltation of irrigation dams, higher transpiration of crops and water stress resultingin low crop yield, crop failure and food insecurity. The research also highlights anthropogenic activities that have influencedclimate variability and food production in the region. The research was concluded with suggested strategies to facilitate farmers’adaptation to climate variability.

Erratum to: Water management strategies for hydropower annexation at existing irrigation dams in Japan

Erratum to: Water management strategies for hydropower annexation at existing irrigation dams in Japan

Analysing the Effects of Forest Cover and Irrigation Farm Dams on Streamflows of Water-Scarce Catchments in South Australia through the SWAT Model

To assist water resource managers with future land use planning efforts, the eco-hydrological model Soil and Water Assessment Tool (SWAT) was applied to three catchments in South Australia that experience extreme low flow conditions. Particular land uses and management issues of interest included forest covers, known to affect water yields, and farm dams, known to intercept and change the hydrological dynamics in a catchment. The study achieved a satisfactory daily calibration when irrigation farm dams were incorporated in the model. For the catchment dominated by extreme low flows, a better daily simulation across a range of qualitative and quantitative metrics was gained using the base-flow static threshold optimization technique. Scenario analysis on effects of forest cover indicated an increase of surface flow and a reduction of base-flow when native eucalyptus lands were replaced by pastures and vice versa. A decreasing trend was observed for the overall water yield of catchments with more forest plantation due to the higher evapotranspiration (ET) rate and the decline in surface flow. With regards to effects of irrigation farm dams, assessment on a daily time step suggested that a significant volume of water is stored in these systems with the water loss rate highest in June and July. On an annual basis, the model indicated that approximately 13.1% to 22.0% of water has been captured by farm dams for irrigation. However, the scenario analysis revealed that the purposes of use of farm dams rather than their volumetric capacities in the catchment determined the magnitude of effects on streamflows. Water extracted from farm dams for irrigation of orchards and vineyards are more likely to diminish streamflows than other land uses. Outputs from this study suggest that the water use restrictions from farm dams during recent drought periods were an effective tool to minimize impacts on streamflows.

A Scheme of Analysis for Monitoring Seismic Properties of Dams for Irrigation Based on Records of Existing Seismometers

A Scheme of Analysis for Monitoring Seismic Properties of Dams for Irrigation Based on Records of Existing Seismometers

Supporting Renewables’ Penetration in Remote Areas through the Transformation of Non-Powered Dams

Supplying power to remote areas may be a challenge, even for those communities already connected to the main grid. Power is often transmitted from long distances, under adverse weather conditions, and with aged equipment. As a rule, modernizing grid infrastructure in such areas to make it more resilient faces certain financial limitations. Local distribution may face stability issues and disruptions through the year and—equally important—it cannot absorb significant amounts of locally-produced power. The European policy has underlined the importance of energy production in local level towards meeting energy security and climate targets. However, the current status of these areas makes the utilization of the local potential prohibitive. This study builds on the observation that in the vicinity of such mountainous areas, irrigation dams often cover different non energy-related needs (e.g., irrigation, drinking water). Transforming these dams to small-scale hydropower (SHP) facilities can have a twofold effect: it can enhance the local energy portfolio with a renewable energy source that can be regulated and managed. Moreover, hydropower can provide additional flexibility to the local system and through reservoir operation to allow the connection of additional solar photovoltaic capacities. The developed methodological approach was tested in remote communities of mountainous Greece, where an earth-fill dam provides irrigation water. The results show a significant increase of renewables’ penetration and enhanced communities’ electricity autarky.

Multi-Criteria Environmental Impact Assessment of Alternative Irrigation Networks with an Adopted Matrix-Based Method

Environmental impact assessments (EIA) identify the type, importance, and severity of the environmental consequences of human activities. This study performs an EIA of the Shahriar dam irrigation project in Iran. Physical, biological, and social-economic-cultural criteria and parameters are evaluated in the short and long terms with the Leopold matrix method. Results show that short-term project implementation has its most negative impact in the biological realm (with a score of −48), while long-term implementation would impact most favorably the social-economic-cultural component (+233). A sensitivity analysis of the EIA was employed to determine the relative impacts of the physical, biological, and social-economic-cultural components of the Shahriar irrigation project.

The response of phytoplankton and microlayer-adapted bacteria to monolayer application in a humic, eutrophic irrigation dam.

Repeat applications of artificial monolayers to farm irrigation dams to reduce evaporative loss may adversely affect water quality by enhancing populations of microlayer-adapted bacteria and blue-green algae. The microlayer, subsurface and water column of a 16 ha dam were monitored every two weeks for 18 months, to benchmark the seasonal dynamics of phytoplankton and microlayer-adapted bacteria prior to monolayer application. Results for Secchi depth, total P, total N, chlorophyll a, phytobiovolume and UV254 absorbance, characterise Logan's Dam as humic and hypereutrophic. Seasonal peaks in the cyanobacterial species Microcystis aeruginosa and Anabaena sp. associated with regular thermal stratification periods over summer, exceeded the Queensland algal bloom alert level. Dissolved organic matter derived from aromatic char in the black soil used to construct the dam was the main substrate for microlayer-adapted bacteria. Intermittent monolayer application over seven weeks in late summer temporarily increased surface pressure, indicating a condensed monolayer had formed, with no increase in chemical oxygen demand or in populations of cyanobacteria or microlayer-adapted bacteria. The increase in dissolved organic carbon was well below the concentration recorded after a pump ingress event in late spring. In this humic hypereutrophic irrigation dam, repeat applications of the experimental monolayer formulation did not adversely affect water quality.

Civil engineering heritage: country profile – Albania

This paper is a review of Albania’s civil engineering heritage, one of the series of national profiles being published by Engineering History and Heritage. It is presented under four headings: Albania’s major civil engineering achievements; national and regional recognitions of its engineering heritage; exemplar conservation of engineering structures; and information sources for engineering heritage. The paper discusses engineering structures of heritage importance including three United Nations Educational, Scientific and Cultural Organization World Heritage sites as well as many ancient remains from Illyrian, Greek and Roman times and medieval fortifications and castles. Many buildings and civil engineering structures remain from the later nineteenth and early twentieth centuries, when Albania was first establishing its own identity following independence from the Ottoman Empire. With help from Russia and China until the 1970s and independently since then, Albania has constructed many industries and many civil infrastructure including roads, bridges and over 600 irrigation dams. The paper identifies some organisations in Albania active in helping to conserve its engineering heritage, including the Central Technical Archive of Construction and concludes with a short list of websites and books giving further information about Albanian heritage.

미계측 유역 평균갈수량 산정을 위한 지역회귀모형의 개발

본 연구에서는 미계측 유역의 평균갈수량 추정을 위한 지역회귀모형을 개발하고자 하였다. 12개 다목적댐과 4개의 용수댐에서 관측된 조절되지 않은 유입량 자료로부터 평균갈수량을 산정하였고, 이를 유역면적, 유역경사, 유역밀도, 연평균강수량, 유출곡선지수 등의 유역특성인자와의 상관분석을 통해 다양한 형태의 지역회귀모형을 개발하였다. 평균갈수량의 관측값과 추정값의 비교를 통해 각 회귀모형의 성능을 평가하였고, 유역면적, 연평균강수량, 유출곡선지수를 설명변량으로 하는 회귀모형이 가장 우수한 성능을 보였다. 또한 비유량법과 기존에 개발된 기존회귀모형과의 비교를 통해서 본 연구에서 개발한 모형의 적용성이 가장 우수한 것으로 분석되었다. The purpose of this study is to develop regional regression models to estimate mean low flow for ungauged basins. The unregulated streamflow data observed at 12 multipurpose dams and 4 irrigation dams were analyzed for determining mean low flows. Various types of regression models were developed using the relationship between mean low flows and various sets of watershed characteristics such as drainage area, average slope, drainage density, mean annual precipitation, runoff curve number. The performance of each regression model for estimating mean low flows was assessed by comparison with the results obtained from the observed data. It was found that a regional regression model explained by drainage area, the mean annual precipitation, and runoff curve number showed the best performance. The regression model presented in this study also gives better estimates of mean low flow than the estimates by the drainage-area ratio method and the previous regression model.

Reservoir Operation in View of Effective Utilization of Limited Water in Semi‐Arid Areas The Case of Gumsalasa Earthen Dam Irrigation Scheme in Tigray, Ethiopia

AbstractTigray is one of the semi‐arid and drought‐prone regions of Ethiopia. The rainfed agriculture is characterized by low productivity and the region faces an average annual cereal food deficit of 180 000 t. Realizing these problems, the regional government has been engaged in earthen dam irrigation development activities since 1995. So far 44 earthen dams with related irrigation facilities have been constructed.The Gumsalasa earthen dam was constructed in 1995 with a reservoir capacity of 1.9 million m3, which irrigates about 67 ha. In Tigray the main irrigation season starts in January, which is four months after the end of the main rainy season. The reservoir is therefore exposed to evaporation during these four months. This demands formulation and implementation of an operational plan that can reduce losses and increase the benefits. In this regard, a change in reservoir operation from the present (January–June) to the proposed (September–January) has shown the possibility of increasing the irrigated area and the number of farmers. This indicates the potential of the proposed change to contribute towards regional food security if it is practised at existing and future earthen dam irrigation schemes in Tigray. Copyright © 2016 John Wiley & Sons, Ltd.