Construction Of New Dams Research Articles

The Modeling and Optimization of a Multi-dam System

In this paper, we present a maintenance plan for the Kariba Dam in Africa. The Kariba Dam, a double curvature concrete arch dam in Zambia's capital, is crucial for regional energy and water management. Ensuring its safety and functionality is essential. This study provides a comprehensive analysis and maintenance plan to safeguard the dam's long-term viability. Our mathematical analysis begins with a threshold evaluation of three proposed options, considering costs such as relocation, dam removal, construction of new dams, repairs, and ecological damage, as well as benefits like energy generation, flood prevention, employment, tourism, and ecological protection. The data-driven analysis indicates that our option is the most economically viable. We assess water management capabilities, using them as a safety coefficient for the dams. We selected 30 seed points along the riverbank to establish dams. Our recommendation is to increase the number of dams and ensure their strategic distribution. An assessment model based on the analytic hierarchy process was then developed, focusing on three factors: safety, economy, and population. We determined the weights of each factor. The optimal scheme was identified through this model, and the sensitivity of the results was also evaluated. The greatest impact under extreme conditions was found. This paper provides the details of the theoretical analysis and the numerical experiments, which include the use of modeling, optimization, mathematical programming, and so on.

China Southern Power Grid’s decarbonization likely to impact cropland and transboundary rivers

Decarbonizing the electricity sector requires massive investments in generation and transmission infrastructures that may impact both water and land resources. Characterizing these effects is key to ensure a sustainable energy transition. Here, we identify and quantify the unintended consequences of decarbonizing the China Southern Power Grid, China’s second-largest grid. We show that reaching carbon neutrality by 2060 is feasible; yet, doing so requires converting 40,000 square kilometers of land to support solar and wind as well as tapping on rivers to build ~32 gigawatts of hydropower. The impact of wind and solar development would span across multiple sectors, since crop and grassland constitute 90% of the identified sites. The construction of new dams may carry major externalities and trickle down to nearby countries, as most dams are located in transboundary rivers. Curbing the international footprint of this decarbonization effort would require additional investments (~12 billion United States dollars) in carbon capture technologies.

Quantitative assessment of sedimentation in Moroccan dam reservoirs: analysis and projections

The siltation of dam reservoirs is the phenomenon that most embarrasses dam managers and water reservoir operators. In Morocco, this phenomenon affects all the watersheds to different degrees. Dam managers schedule bathymetric measurement companies to estimate the quantities of mud deposited in reservoirs. These companies are neither regular in time nor generalized on the 152 large dams of the Kingdom because of the high cost of the bathymetry operations. In our research work, the bathymetric data available for about a century were collected, checked, corrected, and sorted to be exploited.In the next step, we extrapolated over time and updated the siltation rates for each dam according to the trend curves of the evolution of silted volume. Most of these trend curves were linear. For the nonlinear curves, we looked for explanations throughout history. These are dams whose reservoirs have undergone human intervention such as desilting operations or emptying of reservoirs, or following natural phenomena such as drought or exceptional floods. The research work subsequently made it possible to estimate the annual siltation rates for 53 large dams whose reservoir capacities total approximately 92% of that of the entire country. It also revealed an overall siltation rate of 18.14% for the entire country and rates ranging from 10% to 52% for each watershed. The discussions of these results in this article give explanations on the highest rates, based on the natural data of the watersheds in question. These results will help decision-makers to define the priorities of desilting operations or the construction of new dams, help investors and industrialists wishing to extract and use mud from dam reservoirs as raw material, and can also be used in various scientific fields such as dam reservoir management, flood risk prevention, environmental impact studies, spatial planning, and research and development studies.

Potential storage augmentation impacts on hydropower production, irrigation water supply and environmental flows in the Indus Basin in Pakistan

Study regionIndus River basin, Pakistan Study focusThe study assesses the implications on irrigation water reliability, hydropower production and environmental flows to the Indus Delta resulting from the implementation of large new storages on the Indus River. These large dams have the potential to impact water supply security of the Indus Basin Irrigation System which operates with a priority of maximising irrigation supply via the 1991 Water Apportionment Accord. Implementation of the Accord under future scenarios involving new large dams is open to interpretation. This study uses the daily time step Indus River System Model to simulate the potential impact of these new large dams on hydropower production, irrigation water supply and flows to the Indus Delta under different Accord interpretations. New insights for the regionPakistan possesses significant potential for increasing hydropower production from the Indus River through the construction of new reservoirs, which could raise the nationwide share of electricity generated from hydropower from 29% to 44–53%. This study demonstrates that augmenting storage capacity can yield threefold benefits – improved end-of-system environmental flows, more reliable irrigation supply for the Rabi season, and increased hydropower production. Additionally, this modelling approach can be instrumental in strengthening the existing water governance arrangements when considering the construction of new dams, thereby improving the health of the Indus delta ecosystem through the construction of dam construction.

Mutually beneficial outcomes for hydropower expansion and environmental protection at a basin scale

Reshaping the scale of planning for hydropower development, from reaches to basin-scales, has been recommended as a more effective way to ameliorate the environmental impacts of hydropower. One approach is identifying mutually exclusive areas where development is precluded for conservation purposes and areas of low conservation value that present fewer barriers to development. This strategy, however, is less adoptable in developed countries where hydropower is already widespread and large-scale construction of new dams is unlikely. To broaden the adoption of basin-scale planning, alternative approaches and planning tools are needed for identifying mutually beneficial opportunities for simultaneous increases in hydropower capacity while improving environmental conditions. In this study, we present the Basin Scale Opportunity Assessment as a methodology to improve environmental conditions through either direct (on-site) or indirect (off-site) mitigation. We assess whether direct or indirect mitigation activities lead to optimal results in terms of added hydropower, environmental improvement, and monetary cost at a basin scale. We present two case studies for the Connecticut River and Roanoke River Basins, USA. Significant opportunities for expanding hydropower generating capacity are numerous in both basins. Results suggest that total hydropower capacity could be increased 4 to 7 % in the Roanoke and Connecticut Basins, respectively, without new dam construction and with net improvements in environmental conditions. We found that environmentally and economically optimal win-win strategies for increasing hydropower capacity and improving environmental conditions included improving environmental conditions in rivers downstream of existing dams. Off-site mitigation opportunities, such as dam removal and wetland mitigation, were identified as optimum solutions for achieving net environmental improvements only when they were associated with new hydropower construction. Our results demonstrate that opportunities to increase hydropower capacity and improve environmental conditions are expanded by viewing cumulative benefits at basin scales; however, increasing regulatory flexibility may be required to realize these opportunities.

Deep learning for check dam area extraction with optical images and digital elevation model: A case study in the hilly and gully regions of the Loess Plateau, China

AbstractCheck dams are widely used on the Loess Plateau of China to control soil and water loss, develop agricultural land and improve watershed ecology. Detailed information on the spatial distribution of check dams and the area of dam land is critical for quantitatively evaluating hydrological and ecological effects, planning the construction of new dams and repairing damaged dams. Therefore, this research presents a method that integrates deep learning and geospatial analysis to facilitate the extraction of check dam areas in broad areas from high‐resolution Gaofen‐2 (GF‐2) multispectral imageries, including red (R), green (G), blue (B) and near‐infrared (NIR) bands and digital elevation model (DEM). First, we generated three datasets with different band combinations (RGB, RGB + NIR and RGB + DEM) using GF‐2 remote sensing images combined with Advanced Land Observing Satellite—the Phased Array type L‐band Synthetic Aperture Radar DEM data to determine the optimal data combination for dam area extraction. Next, four widely used semantic segmentation networks—Fully Convolutional Network (FCN), U‐Net, PSPNet and DeepLabv3+—were modified to support the arbitrary number of input channels and evaluated for check dam area extraction. Finally, the check dam candidate areas in the Yan River basin were extracted from DEM using geospatial analysis to optimize the dam area extraction results. The results showed that all deep learning (DL) models could extract dam areas quickly and accurately with mean intersection over union and overall accuracy values >85% and >98%, respectively. PSPNet had the best performance for testing datasets with different band combinations. We also found that the DL models in the RGB + DEM images had the best remote sensing image segmentation results, avoiding many miss‐classified pixels. The F1 scores in the RGB + DEM test dataset for FCN U‐Net, PSPNet and DeepLabv3+ reached up to 92%, or 3.3%, 2.3%, 1.9% and 3.1% higher than the corresponding values for RGB images. Potential check dam candidate regions (~3969 km2) were obtained for application analysis, which reduced the original area by 50%. The DL models for the RGB + DEM images were applied in the dam candidate regions, extracting 91.9 km2 of agricultural production dam land and 10.6 km2 of runoff and sediment silted dam land. The extraction results will facilitate quantitative analyses of check dams, improve the management of these structures and promote the efficiency of controlling soil losses.

Diminishing storage returns of reservoir construction

Surface water reservoirs are increasingly being relied upon to meet rising demands in the context of growing population and changing climate. However, the amount of water available in reservoirs (and the corresponding trends) have not been well quantified at the global scale. Here we use satellite observations to estimate the storage variations of 7245 global reservoirs from 1999 to 2018. Total global reservoir storage has increased at a rate of 27.82 ± 0.08 km3/yr, which is mainly attributed to the construction of new dams. However, the normalized reservoir storage (NS)—the ratio of the actual storage to the storage capacity—has declined by 0.82 ± 0.01%. The decline of NS values is especially pronounced in the global south, while the global north mainly exhibits an NS increase. With predicted decreasing runoff and increasing water demand, these observed diminishing storage returns of reservoir construction will likely persist into the future.

Научная методика составления паспорта плотины в течение ее жизненного цикла на основе инженерного сервейинга и геодезического мониторинга

The public and property risks associated with dam failures are very high, due to the location of settlements in areas of potential flooding, as well as the construction of new dams in less than ideal areas (in far from ideal territories).
 Due to the variety of risks that threaten dam structures and their surroundings, it is necessary to identify the possible causes and consequences of dam failure, and then develop a program to improve its safety. The monitoring of dam behavior/performance needs to start from the first days of construction and continue throughout the life cycle.
 The conducted study suggests a scientific methodology for the preparation of annual dam passports, which should contain all the data and information obtained from the date of the dam's creation until the issuance of the passport. The study also makes recommendations on the types of data and information that should be included in the dam passport, which will enable workers and experts in the field of dam life cycle monitoring, as well as responsible persons, to take the necessary measures and proactively resolve any problems that exist or may occur.

Harnessing the power of environmental flows: Sustaining river ecosystem integrity while increasing energy potential at hydropower dams

Hydropower comprises the largest portion of the world's renewable energy portfolio yet induces significant environmental effects in river and floodplain ecosystems. Many countries are seeking to increase hydropower capacity primarily through the construction of new dams; however, this overlooks the potential energy that can be gained from optimizing existing hydropower infrastructure. Environmental regulatory protocols globally, and especially in the US, require hydropower facilities to provide environmental flows to downstream riverine ecosystems. Most of these facilities, however, fail to capture additional hydropower energy from these releases, such as passing them through smaller turbines. Herein, we conducted a US-wide analysis of the potential additional hydropower capacity and generation that could be available if environmental flows were harnessed for energy. We used two approaches based on availability of information: one reliant on available stream flow data to identify specific optimal turbine sizes, and another using a design-envelope approach, to accommodate situations where flow data was unavailable. Using available historical flow data and plant characteristics from over 200 existing hydropower facilities, the addition of minimum flow turbines could provide up to 730 MW of capacity and generate nearly 1.8 TWh of energy annually. Across the remaining hydropower fleet, the envelope approach suggests there may be anywhere from 12 TWh to 66 TWh of additional energy, supplied from a capacity increase of 2.5 GW–13.5 GW annually. Ultimately, this suggests that uncaptured environmental flows provide anywhere from 4% to 18% potential increase in US hydropower capacity and 4%–24% increase in generation.

The potential of unused small-scale water reservoirs for climate change adaptation: A model- and scenario based analysis of a local water reservoir system in Thuringia, Germany

The 6th Intergovernmental Panel on Climate Change (IPCC) report (2021) stated that hot extremes have become more frequent and intense across most land regions in the past decades. It is projected that the changing climatic conditions in Germany and Thuringia in particular will lead to a higher frequency of drought events. Thus, it is vital to develop local adaptation strategies to mitigate the effects of droughts on agriculture to ensure future crop production. Water resource infrastructure has a critical role in planning future climate change adaptation measures that are sustainable. As the construction of new dams and reservoirs is controversial, it is preferable to use existing infrastructures, if they are suitable. Small-scale water management reservoirs built in Thuringia during the GDR (German Democratic Republic) and decommissioned after the German reunification were examined in this study to determine whether their reuse could be considered as a potential adaptation strategy. For this purpose, three reservoirs in Thuringia were selected. The impact of climate change on soil moisture, water availability and crop production, and the use of water from the reservoirs to meet future irrigation needs were modeled using the Water Evaluation and Planning system (WEAP). The modeled climatic changes have direct effects on the soil moisture status, leading to a higher water demand of the local agriculture. The results show that the crop water needs could double between near future (2020–2040) and distant future (2071–2100). However, predicted declines in yields can be mitigated by irrigation; modeling results indicate that supplemental irrigation with reservoir water mitigates projected losses and even allows 6.2–13.5% more crop production. Hence, the reuse of the reservoirs is worth to be considered as an adaptation strategy by policymakers. In addition to a cost-benefit analysis for future evaluation of the reservoirs, local user interests and demands need to be included avoiding conflicts about water. In general, WEAP as a modeling tool and the findings of the study show, that this research approach could be used to investigate the potential adaptive capacity of other small-scale water infrastructures.

Energy and economic study of the increased energy production of cascaded hydroelectric plants due to the heightening of the upstream reservoir: A case study in Cipó-Rio das Antas dam

Increased hydroelectric reserve capacity through cascade heightening is one option for increasing its overall output. Such increases are relevant to the circumstances faced by the Brazilian energy matrix, which is heavily dependent on hydroelectric dams and where many environmental restrictions may slow the construction of new dams. Thus, this article studies the increase in storage volume in a Brazilian dam and evaluates the gains in terms of electricity generation and water flow on downstream dams. A dam located on the Antas River, in Brazil, was chosen as the study area. Flow regulation capacity from the increased height was determined through multiple hydrological methods which enabled the estimation of energy gains on downstream dams. The results obtained demonstrate that, by increasing the dam height by 1 m to the upstream structure, there would be a regularized flow of 2.47 m3/s along with an increase in energy production of 3.34 GWh/y throughout the entire downstream cascade. Investments of 500,000 USD would be necessary to add an additional meter to the dam construction height, which would be paid off over a period of five years with the increase in energy production. The methodology herein presented can be replicated in other regions, thus aiding in greater efficiency and operation of hydroelectric power plants.

Behaviour of Compacted Filtered Iron Ore Tailings–Portland Cement Blends: New Brazilian Trend for Tailings Disposal by Stacking

Failures of tailings dams, primarily due to liquefaction, have occurred in Brazil in recent years. These events have prompted the Brazilian government to place restrictions on the construction of new dams, as iron ore tailings deposited behind upstream dams by spigotting have been shown to have low in situ densities and strengths and are prone to failure. This work proposes a new trend for tailings disposal: stacking compacted filtered ore tailings–Portland cement blends. As part of the proposal, it analyses the behaviour of compacted iron ore tailings–Portland cement blends, considering the use of small amounts of Portland cement under distinct compaction degrees. With the intention of evaluating the stress–strain–strength–durability behaviour of the blends, the following tests were carried out: unconfined compression tests; pulse velocity tests; wetting–drying tests; and standard drained triaxial compression tests with internal measurement of strains. This is the first study performed to determine the strength and initial shear stiffness evolution of iron ore tailings–Portland cement blends during their curing time, as well friction angle and cohesion intercept. This manuscript postulates an analysis of original experimental results centred on the porosity/cement index (η/Civ). This index can help select the cement quantity and density for important design parameters of compacted iron ore tailings–cement blends required in geotechnical engineering projects such as the proposed compacted filtered iron ore tailings–cement blends stacking.

Are African irrigation dam projects for large-scale agribusiness or small-scale farmers?

The economic development of rural economies across the global south is often related to access to water and the development of water infrastructure. It has been argued that the construction of new dams would unleash the agricultural potential of African nations that are exposed to seasonal water scarcity, strong interannual rainfall variability, and associated uncertainties in water availability. While water security is often presented as the pathway to poverty alleviation and invoked to justify large dam projects for irrigation, it is still unclear to what extent small holders will benefit from them. Are large dams built to the benefit of subsistence farmers or of large-scale commercial agriculture? Here we use remote sensing imagery in conjunction with advanced machine learning algorithms to map the irrigated areas (or ‘command areas’) that have appeared in the surroundings of 18 major dams built across the African continent between 2000 and 2015. We quantify the expansion of irrigation afforded by those dams, the associated changes in population density, forest cover, and farm size. We find that, while in the case of nine dams in the year 2000 there were no detectable farming patterns, in 2015 a substantial fraction of the command area (ranging between 8.5% and 96.7%) was taken by large-scale farms (i.e., parcels >200 ha). Seven of the remaining 9 dams showed a significant increase in average farm size and number of farms between 2000 and 2015, with large-scale farming accounting for anywhere between 5.2% and 76.7% of the command area. Collectively, these results indicate that many recent dam projects in Africa are associated either with the establishment of large-scale farming or a transition from small-scale to mid-to-large scale agriculture.

Global hydropower expansion without building new dams

Reducing global carbon emissions will require large-scale transitions from fossil fuels to renewable energy resources. Hydropower will likely play a role in those transitions as it provides reliable energy storage while counter-balancing intermittent renewables. However, the construction of new dams comes at significant environmental costs to river ecosystems. An optimal future considers how to maximize the benefits of hydropower while minimizing environmental impact through revitalizing existing infrastructures. Herein, we quantify this potential using a spatially comprehensive global inventory of geolocated dams used for purposes other than hydropower, and augment these results with modelled estimates of small, unmapped dams. Furthermore, we examine increases in hydropower potential from efficiency upgrades at existing hydro-plants. These opportunities afford non-invasive increases in hydropower in populated areas neighbouring biodiversity hot spots. Overall, we estimate that these contributions could potentially provide up to a 9% increase to current global hydropower, potentially reducing the costs of construction and transmission, all while offsetting impacts to biodiversity and river ecosystems incurred by planned new hydropower construction.

Socioenvironmental impacts of dam in the Jari Valley, Amapa, Brazil: community perceptions

Abstract The expansion of the Brazilian electricity sector is based on the construction of new dams. However, dams generate impacts, especially on riverine communities. Thus, this paper examined the local communities perceptions about the socioeconomic and environmental impacts of the Santo Antônio do Jari Dam, in Amapá. Data were obtained through surveys using the snowball sampling method. To analyze the perception data the Bardin’s analysis of content was used. The research showed that, before the construction of the dam, there was a very intimate bond between the communities, the environment and the nature, which influenced the communities perceptions mainly regarding environmental impacts, relocation, changes in livelihood and access to natural resources.

Impact of dams and climate change on suspended sediment flux to the Mekong delta

The livelihoods of millions of people living in the world's deltas are deeply interconnected with the sediment dynamics of these deltas. In particular a sustainable supply of fluvial sediments from upstream is critical for ensuring the fertility of delta soils and for promoting sediment deposition that can offset rising sea levels. Yet, in many large river catchments this supply of sediment is being threatened by the planned construction of large dams. In this study, we apply the INCA hydrological and sediment model to the Mekong River catchment in South East Asia. The aim is to assess the impact of several large dams (both existing and planned) on the suspended sediment fluxes of the river. We force the INCA model with a climate model to assess the interplay of changing climate and sediment trapping caused by dam construction. The results show that historical sediment flux declines are mostly caused by dams built in PR China and that sediment trapping will increase in the future due to the construction of new dams in PDR Lao and Cambodia. If all dams that are currently planned for the next two decades are built, they will induce a decline of suspended sediment flux of 50% (47–53% 90% confidence interval (90%CI)) compared to current levels (99 Mt/year at the delta apex), with potentially damaging consequences for local livelihoods and ecosystems.

Small hydropower plants as a threat to the endangered pearl mussel Margaritifera margaritifera

Freshwater mussels are undergoing rapid global declines due to habitat loss and fragmentation, among other factors, but little is known about the effects of small hydropower plants. Here we assessed the impact of small hydropower plants on the abundance and size structure of the imperilled pearl mussel Margaritifera margaritifera. For this, we sampled 66 sites in three Portuguese rivers (Mente, Rabaçal and Tuela) located upstream and downstream of dams and within the reservoirs. Pearl mussels were significantly more abundant upstream than downstream of dams (97.4% more) or within reservoirs (98.5% more). In addition, juveniles were mostly found upstream of dams. The most significant environmental alterations that explained the observed patterns were related to changes in sediment characteristics (accumulation of fine sediments and organic matter in reservoirs) and water chemistry, most notably suspended solids (highest values in reservoirs) and dissolved oxygen (lowest values in reservoirs). Overall, results show that small hydropower plants can deeply affect pearl mussel populations: specimens almost disappeared from the areas within the reservoirs and sites located downstream only retained adults without signs of recent recruitment. Future management measures devoted to the conservation of pearl mussels should take into account the results reported here to avoid the construction of new dams in pearl mussel rivers; improve management of the river flow in downstream areas; and consider the decommissioning of dams in pearl mussel rivers with a particular attention devoted to the re-naturalization of river sections under the influence of the reservoir and downstream areas.

An Engineering Perspective of Water Sharing Issues in Pakistan

Water sharing within the states/provinces of a country and cross-border is unavoidable. Conflicts between the sharing entities might turn more severe due to additional dependency on water, growing population, and reduced availability as a result of climate change at many locations. Pakistan, being an agricultural country, is severely water stressed and heading toward a worsening situation in the near future. Pakistan is heading toward water scarcity as water availability in the Indus basin is becoming critical. Being a downstream riparian of India and Afghanistan in the Indus basin, water availability depends on the releases of water from both countries. The Indus Water Treaty is governing the water distribution rights between India and Pakistan. However, there exists no proper agreement between Pakistan and Afghanistan and the construction of new dams on the Kabul River is another threat to water availability to Pakistan. Correct implementation of the Indus Water Treaty with India is required, together with an effective agreement with Afghanistan about the water sharing. In addition to water shortage, poor management of water resources, inequitable sharing of water, lack of a systematic approach, old-fashioned irrigation practices, and growing agricultural products with large water footprints are all exacerbating the problem. The water shortage is now increasingly countered by the use of groundwater. This sudden high extraction of groundwater is causing depletion of the groundwater table and groundwater quality issues. This water shortage is exacerbating the provincial conflicts over water, such as those between Punjab and Sindh provinces. At one end, a uniform nationwide water allocation policy is required. At the same time, modern irrigation techniques and low-water-footprint agricultural products should be promoted. A fair water-pricing mechanism of surface water and groundwater could be an effective measure, whereas a strict policy on groundwater usage is equally important. Political will and determination to address the water issues are required. The solutions must be based on transparency and equity, by using engineering approaches, combined with comprehensive social support. To develop a comprehensive water strategy, a dedicated technopolitical institute to strengthen the capabilities of nationwide expertise and address the issues on a regular basis is required to overcome the complex and multidimensional water-related problems of the country.

Studying land use dynamics using decadal satellite images and Dyna-CLUE model in the Mahanadi River basin, India.

Population growth rate indicates the proportional rate of settlement expansion and landscape modification in any river basin. The Mahanadi River basin (MRB), which is a densely populated, cropland and forest-dominated landscape, is selected as a case study area for studying the nature of built-up expansion and the corresponding land cover modifications. Satellite data-derived land use/land cover (LU/LC) maps for the years 1995, 2005, and 2015 were used for identification of landscape changes during the past three decades. One of themajor LU/LC changes are observed in terms of increase in the water, which may be attributed to construction of new dams at the cost of the croplands and forest areas. Conversion of forest to cropland and expansion and densification of built-up areas in and around the existing built-up areas are also identified as a major LU/LC change. The geostatistical analysis was performed to identify the relationship between LU/LC classes with drivers, which showed that built-up areas were more in topographically flat terrain with higher soil depth, and expanded more around the existing built-up areas; cropland areas were more at lower elevation and less sloppy terrain, and forest areas were more at higher elevation. The LU/LC scenario of 2025 was projected using a spatially explicit dynamic conversion of land use and its effects (Dyna-CLUE) modeling platform with the LU/LC change trends of past 10 years (2005-2015) and 20 years (1995-2015). The major LU/LC changes observed during 2005-2015 were built-up expansion by 36.53% and deciduous forest and cropland reduction by 0.35% and 0.45%, respectively. Thus, the corresponding predicted change during 2015-2025 estimated built-up expansion by 25.70% and deciduous forest and croplands loss by 0.43% and 0.35%, respectively. On the other hand, during 1995 to 2015, the total built-up expansion and deciduous forest and cropland reduction were observed 50.79%, 0.45%, and 0.73%, respectively. Thus, the predicted changes during 2015-2025 were estimated as 18.48% built-up expansion and 0.22% and 0.21% deciduous forest and cropland loss. However, with the conditions of restricted deforestation and less landscape modification, the LU/LC projections show less built-up area expansion, reducing the cropland, fallow land, plantation, and waste land. The reduced numbers of land cover conversions types during 2005-2015 compared with 1995-2005 indicate more stabilized landscape. The input LU/LC maps and statistical analysis demonstrated the landscape modifications and causes observed in the basin. The model projected LU/LC maps are giving insights to possible changes under multiple pathways, which will help the agriculture, forest, urban, and water resource planners and managers in improved policy-making processes.

A basin-wide approach for water allocation and dams location-allocation

Construction of new dams in undeveloped transboundary basins causes two serious disputes between the stakeholders: conflicts over more water interest and over the new dams’ locations. Hence, water development planning of these basins needs to be done in conjunction with the examination of stakeholders’ new water shares. This study extends the model presented in Roozbahani et al. (Water Resour Manag 31:4539–4556, 2017) to be multi-objective and applies the methodology outlined in Roozbahni et al. (Ann Oper Res 229:657–676, 2015a) to solve the model. The proposed three steps approach determines the equitable allocation of the surface water of an undeveloped transboundary basin while determining optimal number, locations and capacities of new dams. The first step utilizes a mixed-integer-multi-objective model to outline the water shares of stakeholders, as well as optimal dam locations for a given number of dams. Using a sensitivity analysis, the second step pinpoints the required number of dams. The role of third step is the exploration of the dams’ lowest possible capacities. Environmentally, our approach takes the entire watershed’s water requirements into account. We have applied the proposed approach to the Sefidrud Basin, a transboundary basin located in Iran. The results of the approach show that, to significantly improve the security of the Sefidrud Basin’s water supply, three new dams would be optimal.