Flood Control Reservoir Research Articles

Simulation of Flood-Control Reservoirs: Comparing Fully 2D and 0D–1D Models

Flood-control reservoirs are often used as a structural measure to mitigate fluvial floods, and numerical models are a fundamental tool for assessing their effectiveness. This work aims to analyze the suitability of fully 2D shallow-water models to simulate these systems by adopting internal boundary conditions to describe hydraulic structures (i.e., dams) and by using a parallelized code to reduce the computational burden. The 2D results are also compared with the more established approach of coupling a 1D model for the river and a 0D model for the reservoir. Two test cases, including an in-stream reservoir and an off-stream basin, both located in Italy, are considered. Results show that the fully 2D model can effectively handle the simulation of a complex flood-control system. Moreover, compared with the 0D–1D model, it captures the velocity field and the filling/emptying process of the reservoir more realistically, especially for off-stream reservoirs. Conversely, when the basin is characterized by very limited flood dynamics, the two approaches provide similar results (maximum levels in the reservoir differ by less than 10 cm, and peak discharges by about 5%). Thanks to parallelization and the inclusion of internal boundary conditions, fully 2D models can be applied not only for local hydrodynamic analyses but also for river-scale studies, including flood-control reservoirs, with reasonable computational effort (i.e., ratios of physical to computational times on the order of 30–100).

From single to multi‐purpose reservoir: A framework for optimizing reservoir efficiency

AbstractThe prevailing challenge centers on the limited application of single‐purpose flood control reservoirs transitioning to multi‐purpose reservoirs, which, despite their potential, often fall short in addressing the escalating demands for diverse water resource management. These challenges are compounded by outdated operational rules and changing environmental conditions. This research develops a framework to enhance the dual functionality of reservoirs, initially designed for flood control, to also support water supply through the determination of maximum safe water levels (MSWLs). Utilizing historical inflow data and reservoir simulation models, the study identifies opportunities for optimizing United States Army Corps of Engineers Louisville District reservoirs. It highlights certain reservoirs as ideal for augmenting water supply capabilities without compromising flood control performance. Others remain critical for flood management due to limited water supply potential, underscoring the importance of maintaining a focus on flood control. The findings illuminate the intricate balance required between managing flood risks and enhancing water supply, indicating that precise operational adjustments can significantly improve reservoir sustainability and efficiency. This method offers a viable pathway to convert single purpose reservoirs into multi‐purpose reservoirs, meeting growing water demands while ensuring robust flood mitigation, and making a step toward better water utilization.

Linking Nutrient Dynamics with Urbanization Degree and Flood Control Reservoirs on the Bahlui River

This work analyzed the nutrient dynamics (2011–2022) and discharge (2005–2022) for the Bahlui River at four distinctive locations: Parcovaci—a dam-protected area that has been untouched by agriculture or urbanization; Belcesti—a primarily agricultural area, also dam-protected; Podu Iloaiei—a region influenced by agriculture and urbanization; and Holboca—placed after a heavily urbanized area. The analysis focused on determining a series of statistical indicators using the Minitab 21.2 software. Two drought intervals and one flood interval were analyzed to highlight daily discharge evolution during the selected period, showing that the constructed reservoirs successfully control the streamflow. For the entire period, the evolution of mean and median values of the streamflow is consistent, considering the locations’ positions from the source to the river’s end. The total nitrogen and total phosphorus were selected as representative quality indicators. The study follows the influence of the analyzed areas’ characteristics and reservoirs’ presence on nutrient dynamics. The results showed that the most influential factor that impacts nutrient dynamics is the reservoirs’ presence, which controls the discharge, creates wetlands and swamps, and implicitly impacts nutrient concentration.

Potential for managing pool levels in a flood-control reservoir to increase nitrate-nitrogen load reductions.

Few strategies are available to reduce nitrate-nitrogen (NO3 -N) loads at larger landscape scales, but flood control reservoirs are known to reduce riverine loads. In this study, we evaluated the potential to increase nitrogen (N) loss at Lake Red Rock, a large reservoir located in central Iowa, by evaluating the inundation of sediments deposited at the reservoir inflow. Sediment samples were collected at 51 locations in the lower delta region and analyzed for particle size and nutrient content. Nitrogen loss rates in delta sediments were determined from laboratory assays, and satellite imagery was used to develop a rating curve to quantify land area inundated within the delta. The daily mass of NO3 -N reduced with delta inundation was estimated by applying the mean N 24-h loss rate (0.66g N m2 day-1 ) by the area of inundation (m2 ). Results indicated that raising pool elevations to inundate more of the delta would result in greater N losses, ranging from 2 to 377 Mg per year. Potential N loss of 102 Mg achieved by increasing pool stage by 0.5m would be equivalent to installing nearly 650 edge-of-field practices in the watershed. Although more work is needed to integrate with an existing environmental pool management plan, study results indicate that reservoir management could achieve N reductions at a novel landscape scale.

Comparing bluegill growth among newly constructed, renovated, and established flood-control reservoirs in southeastern Nebraska

Perrion MA, Lebsock JR, Werner JP, Blank AJ, Miller BT. 2024. Comparing bluegill growth among newly constructed, renovated, and established flood-control reservoirs in southeastern Nebraska. Lake Reserv Manage. 40:57–65. Multiple reservoirs have been constructed in the last 10 yr in southeastern Nebraska for flood control and recreational purposes. In addition, other existing reservoirs have undergone major renovations in the same time period to remove sediment and aquatic invasive species. This situation created the opportunity to compare bluegill (Lepomis machrochirus) growth between newly constructed, renovated, and established reservoirs. This study analyzed bluegill growth data from 8 different flood-control reservoirs in southeastern Nebraska in 2021 and 2022. The study objectives were to (1) determine aging precision of scales and otoliths in bluegill and (2) evaluate bluegill growth among new, renovated, and established flood-control reservoirs. For all bluegill collected during the study, exact percent agreement for otolith ages between 2 readers was 89.6%, and percent agreement was 99.1% within 1 yr of age. For scales, exact percent agreement was 48.0% and 84.3% within 1 yr. Mean lengths at age for all reservoir types were similar for age-2 bluegill, whereas age-3 bluegill had longer mean lengths in renovated reservoirs than in either new or established reservoirs. Mean lengths of age-4 bluegill from new and renovated reservoirs were similar, but greater than mean lengths of age-4 bluegill in established reservoirs. Results of this study further demonstrate the greater precision of whole view otolith aging for bluegills compared to scale estimates and will benefit future managers making management decisions for bluegills. Managers can also use information ascertained from bluegill growth metrics to further manage bluegill populations based on reservoir age and management objectives.

3-D-HN investigations of the plan condition at the Watzdorf flood control reservoir

3-D-HN investigations of the plan condition at the Watzdorf flood control reservoir

Design principles for engineering wetlands to improve resilience of coupled built and natural water infrastructure

Intensifying climate extremes and the ageing of built infrastructure have prompted the idea of replacing the ageing built infrastructure with natural infrastructure. In this paper, we discuss how a distributed portfolio of smaller wetlands performs compared to a flood control reservoir in terms of flood mitigation. Using a framework of a loosely coupled land surface model with a hydrodynamic model, in the Brazos basin (Texas), we find that (i) two smaller wetlands have more impact on flood mitigation than one double sized wetland, and (ii) creating multiple wetlands (prioritized based on storage) increases flood mitigation. Further, we find that a portfolio of wetlands equivalent to the size of the submergence area of the biggest flood control reservoir (Whitney) in the basin, can create additional flood control storage, equivalent to ∼10% of the total storage of Lake Whitney. Creating a portfolio of wetlands can increase the overall resiliency of the basin.

Enhancing the representation of water management in global hydrological models

Abstract. This study enhances an existing global hydrological model (GHM), Xanthos, by adding a new water management module that distinguishes between the operational characteristics of irrigation, hydropower, and flood control reservoirs. We remapped reservoirs in the Global Reservoir and Dam (GRanD) database to the 0.5∘ spatial resolution in Xanthos so that a single lumped reservoir exists per grid cell, which yielded 3790 large reservoirs. We implemented unique operation rules for each reservoir type, based on their primary purposes. In particular, hydropower reservoirs have been treated as flood control reservoirs in previous GHM studies, while here, we determined the operation rules for hydropower reservoirs via optimization that maximizes long-term hydropower production. We conducted global simulations using the enhanced Xanthos and validated monthly streamflow for 91 large river basins, where high-quality observed streamflow data were available. A total of 1878 (296 hydropower, 486 irrigation, and 1096 flood control and others) out of the 3790 reservoirs are located in the 91 basins and are part of our reported results. The Kling–Gupta efficiency (KGE) value (after adding the new water management) is ≥ 0.5 and ≥ 0.0 in 39 and 81 basins, respectively. After adding the new water management module, model performance improved for 75 out of 91 basins and worsened for only 7. To measure the relative difference between explicitly representing hydropower reservoirs and representing hydropower reservoirs as flood control reservoirs (as is commonly done in other GHMs), we use the normalized root mean square error (NRMSE) and the coefficient of determination (R2). Out of the 296 hydropower reservoirs, the NRMSE is > 0.25 (i.e., considering 0.25 to represent a moderate difference) for over 44 % of the 296 reservoirs when comparing both the simulated reservoir releases and storage time series between the two simulations. We suggest that correctly representing hydropower reservoirs in GHMs could have important implications for our understanding and management of freshwater resource challenges at regional-to-global scales. This enhanced global water management modeling framework will allow the analysis of future global reservoir development and management from a coupled human–earth system perspective.

HABs and HAB nots: Dynamics of phytoplankton blooms across similar oligotrophic reservoirs

Increasing frequency and intensity of cyanobacterial Harmful Algal Blooms (HABs) threaten human and aquatic ecosystem health. Improving our understanding of HABs across a range of systems will be critical to understanding and potentially minimizing risk, especially where HABs are occurring in less productive and less studied waterbodies. Here, the characteristics and annual dynamics of phytoplankton communities were examined, focusing on the timing, magnitude, and predictability of cyanobacterial blooms in five multi-purpose flood-control reservoirs from the Willamette Basin, Oregon, USA. A high similarity in phytoplankton composition and consistency in the timing of cyanobacterial dominance was hypothesized to occur across these oligotrophic reservoirs. However, periods of dominance by potentially HABs producing genera were inconsistent both in their timing and abundances among reservoirs and across years within each reservoir. The lack of regional predictability indicates the importance of local drivers in the formation, intensity, and composition of phytoplankton blooms. These findings have important implications for reservoir management and safeguarding freshwater drinking sources, as not all reservoirs appear to experience cyanobacterial blooms at the same time, demonstrating non-concurrent risks of HABs.

3-D-HN investigations at the Watzdorf flood control reservoir

3-D-HN investigations at the Watzdorf flood control reservoir

Long-term nitrate-nitrogen reductions in a large flood control reservoir

Flood-control reservoirs are common in the U.S. and several are located in highly agricultural regions of the Midwest. In this study, a mass balance of annual and seasonal NO3-N concentration and load reductions was calculated for Lake Red Rock, a large flood-control reservoir located on the Des Moines River downstream of the City of Des Moines, Iowa. Utilizing rare long-term upstream and downstream NO3-N monitoring records extending back in time 42 years and combining this with estimates from tributary inputs, Lake Red Rock reservoir was found to remove an average of 7,379 Mg NO3-N per year, representing 12.4 % of the NO3-N inputs to the reservoir. Annual variations in NO3-N loss rate varied considerably (-2.9 % to 41.3 %) and were significantly related to annual reservoir water retention time. Combining study results with literature data, annual NO3-N reduction in Midwestern flood-control reservoirs was logarithmically related to average annual water retention time. Although flood-control reservoirs are designed primarily for flood protection, manipulating the reservoirs to achieve longer water retention times, particularly during periods of high NO3-N concentrations and loads, could be a strategy to alleviate impairments at downstream water suppliers and help state and federal agencies meet NO3-N reduction goals.

Multi-objective robust optimization of reservoir operation for real-time flood control under forecasting uncertainty

Flood control operation is one of the effective measures to reduce flood risks. Since flood forecasting plays a critical role in real-time reservoir flood control operation, it is necessary to involve forecasting uncertainty in the optimal reservoir operation to inform decision-making. It has always been a difficult task to reduce flood risks by adjusting flood control strategies. To tackle this challenge, this study developed a multi-objective robust optimization methodology for real-time reservoir flood control operation, which mainly coped with forecast uncertainty. Three machine learning (ML) models, including back propagation neural network (BP), long short-term memory neural network (LSTM) and extreme learning machine (ELM) were adopted to forecast the short-term reservoir inflow. A stacking ensemble multi-ML model (SEM) was then applied to integrate the forecasting results of the above models. Furthermore, a multi-objective robust optimal operation model (MOROU) integrating both upstream and downstream safety was established to reduce flood risks and evaluate the impact of forecasting uncertainty on the reservoir operation. To maximize the efficiency of reservoir utilization, this study defined a new indicator of reservoir reserved capacity adaptation (RRCA) as one of the optimization indicators. To better solve the complex multi-objective problem, a scenario to point (STP) method was proposed for searching robust solutions of multi-objective optimization models. Methodologies were validated through an application to the Lishimen reservoir, China. Three main conclusions were derived from the study: (1) Three ML models performed well in flood forecasting with BP being slightly better than the other two, and the SEM method was found to be able to incorporate the characteristics of each model, outperforming the individual models; (2) MOROU showed a narrower distribution of flood risk both upstream and downstream and achieved an approximately 1.5% reduction in the maximum value of the highest water level; (3) RRCA was verified to enable to reduce the discharge flow by an average of 4.52% without occupying additional flood control reservoir capacity, confirming that it can be used as an optimization indicator to improve the utilization of the reservoir. The proposed method can provide robust strategies for real-time reservoir flood control under forecast uncertainty.

Analisis Daya Tampung Waduk Sebagai Pengendali Banjir di Kawasan Sungai Wanggu

Reservoir Boulevard is part of the flood control system in the city of Kendari, like other areas in Indonesia. Wanggu Reservoir is located in Lepo Lepo Village, Baruga District, Kendari City. The reservoir has a storage volume of 267.142m3. danluas DAS wanggu 348,75 km2. This flood control reservoir functions to accommodate flood overflow from the Wanggu River when it rains with high intensity. So in this study to determine the capacity of the reservoir capacity from year to year, a design rain analysis was carried out with return periods of 2, 5, 10, 25, 50, 100 years. It is necessary to analyze the design rainfall to find out whether the reservoir can reduce flooding for up to 100 years or not. In the rain analysis this plan uses the log person type III method and the flood discharge analysis uses the Rational Method. From the research results, it was found that the flood discharge with a return period of 100 years is 9,670m3/the.

Моделирование гидрографа максимального стока как часть задачи трансформации паводка через гидроузел

Modeling ofthe maximum flow hydrographs during spring flood is interpretedas part of a more general task as extreme floods transit throw spillway structures accounting the cutting of maxima in flood control reservoirs. A general statement of the problem related to solving the problem of floods and related economic and environmental damages requiring carrying out complex compensatory and protective water management and hydraulic engineering measures is formulated. The solution of the general problem is not considered, but the authors’ link to the relevant publications is given. The presence of important infrastructure facilities, industrial enterprises and agricultural land can significantly reduce the class of structures. The method of modeling a maximum hydrograph using the Pearson type I differential distribution function for the cases of single-peak and two-peak hydrographs is proposed. Taking into account previous studies of research, the coefficients of completeness of hydrograph form and asymmetry are accepted as criteria for the correspondence of full-scale and simulated hydrographs. A theoretical justification is given and formulas are derived for the functions of maximum flow and flood volumes depending on time. The modeling algorithm is implemented in an Excel environment using built-in statistical beta distribution functions and an optimization procedure “solver”. Excel program is presented for a set of average parameter values, outlines of hydrographs are constructed depending on the shape coefficient, as well as nomograms of the relationship of the asymmetry coefficient with the shape coefficient depending on the ratio of the maximum flow rate and the volume of the flood. Methodology for a two-peak hydrograph is also considered, which is illustrated by the example of the Sursky hydroelectric complex on the Sura River.

A comprehensive computer aided approach to design of earthen dams of dry flood-control reservoirs

A generalized, comprehensive approach to geotechnical design of earthen dams of dry flood-control reservoirs is developed. It consists of three steps:•In Step 1 three-dimensional (3D) model of terrain and dam subsoil is created. The arrangement of geotechnical layers is reconstructed based on results of geotechnical investigation using geostatistical interpolation, namely, kriging.•Step 2 involves 3D finite element (FE) analysis of transient groundwater flow through the subsoil. Anti-filtration barrier extent is determined by appropriate parametric analysis and the condition of critical hydraulic gradients is verified.•Step 3 concerns deformation assessment and stability analysis. Computations are carried out for selected cross-sections of the dam. At this stage transient coupled problem of deformation and groundwater flow is considered. Stability is assessed with the use of shear strength reduction technique.The proposed approach enables verification of all relevant conditions of limit states. Furthermore, it has been developed in such a way as to enable computationally efficient analysis of considered phenomena. The method constitutes a general framework of design procedure. It can be easily adapted to conform any standard requirements, e.g., by taking adequate values of partial safety factors. Moreover, design solutions can be optimized through parametric analyzes.

The Use of Lime for Drainage of Cohesive Soils Built into Hydraulic Engineering Embankments

This paper examines whether lime can be used for the drainage of cohesive soils built into hydraulic engineering embankments. It is a common practice, as early as the planning stage, to seek to reduce costs and accelerate work while maintaining the quality of work. Although lime stabilisation is not currently a widely used solution in the hydraulic engineering sector, it can play an important role in the future. Lime stabilisation can be considered an optimal solution as it shortens the embankment construction by eliminating the need to replace the soil when it is over-wet. This paper investigates whether it is possible to apply lime treatment in the forming of hydraulic engineering embankments as well as analyses the efficiency of mechanical soil drainage and compares it against chemical drainage (lime stabilisation) based on the example of the construction of the Szalejów Górny dry flood control reservoir located in south-western Poland. It presents the results of geotechnical investigations carried out during the construction phase and compares them with cases reported in the literature. The observation of the construction process reveals a high efficiency and effectiveness of quicklime (CaO) as a stabiliser in the soil used for reservoir dams. Adoption of this technology made it possible to achieve significantly higher embankment formation rates (max. approx. 14,000 m3/week) than when mechanical drainage was used (max. approx. 11,000 m3/week). It was also noted that the lime stabilisation process was significantly independent of unfavourable weather conditions, resulting in frequent high weekly efficiencies. Geotechnical tests on samples of the lime-stabilised soil built into the dam body confirmed the possibility of obtaining favourable strength parameters, particularly with regard to the angle of internal friction, cohesion and degree of plasticity. Therefore, it can be expected that lime will be used more widely in the formation of hydraulic engineering embankments and that soil stabilisation technology will be applied more frequently.

Sedimentation and regulation technologies in the Three Gorges Reservoir

AbstractSedimentation is one of the key technical problems present throughout feasibility demonstration, design, construction, and operation of the Three Gorges Project. Since the Three Gorges Reservoir (TGR) began impoundment operation in 2003, important progress has been made in sedimentation and regulation technologies through systematic research and practices. This paper reveals the asynchronous propagation pattern of flood and sediment peak inflows, sediment movement in the backwater area during drawdown period, sediment flocculation, and sediment deposition that compromises the flood control reservoir storage, and puts forward new sediment regulation techniques, including sediment peak discharge regulation during flood season, siltation reduction in the backwater area during drawdown period, dynamic adjustment of the reservoir level during flood season, and joint sediment regulation in cascade reservoirs. A real‐time monitoring, forecasting and dynamic regulation platform for water and sediment inflow in the TGR was developed; a new mode of dynamic sediment regulation called “regulating sediment for greater benefits” is proposed, which addresses the constraints of sedimentation on the optimal operation of TGR. By enabling more flexible operation, this mode improves the process and pattern of sedimentation, ensures the safety of reservoir operation, and significantly augments the comprehensive benefits of the TGR.

Flood Inflow Estimation in an Ungauged Simple Serial Cascade of Reservoir System Using Sentinel-2 Multi-Spectral Imageries: A Case Study of Imjin River, South Korea

The Imjin River is a representative transboundary river in the Korean Peninsula, originating from North Korea and flowing into South Korea. Upstream of Imjin River, on the North Korean side, is the Hwanggang Dam, with a 350 million m3 of storage capacity, which is in operation for power generation and water supply. The sharing of the operation information of Hwanggang Dam has been limited due to political and military tension. South Korea has constructed the Gunnam Flood Control Reservoir downstream of the Imjin River to prevent potential flood damage due to the urgent and unilateral release from the Hwanggang Dam. However, it is difficult to manage the flood of the Imjin River basin under the situation of limited shared real-time information on the Hwanggang Dam operation. In this study, a hydrological analysis system was established to estimate the inflow and release of the Hwanggang Dam by building a lumped hydrological model and an Auto ROM (Reservoir Operation Method)-based reservoir operation algorithm. To estimate the inflow of the Gunnam Flood Control Reservoir, the water level of the Hwanggang Dam was calculated using the Sentinel-2 multi-spectral images, and the hydrological analysis system was calibrated. The evaluation index of the water level of the ungauged Hwanggang Dam derived from January 2017 to August 2020 using the hydrological analysis system was shown to have a coefficient of determination of 0.76 and an RMSE of 3.97 m. In the case of the flood event in August 2020, the coefficient of determination of the flood inflow in the Gunnam Flood Control Zone was calculated to be 0.86.

Conceptual and Analytical Framework as Flood Risk Mapping Subsidy

There are still gaps in defining values and category classifications of exposed items in quantitative damage analysis. This paper proposes a framework that refines the development of flood risk analysis at a local scale. This study first performs a quantitative risk analysis, based mainly on secondary data; it then attempts to communicate the results graphically, aiming to reduce the financial and human resources required. We propose an easily standardized database in a GIS environment, analyzing the influence of a reservoir for flood control and the construction of replicable local-scale risk curves. Hydrological (HEC-HMS) and 2D hydrodynamic (HEC-RAS) models were used to simulate hydrographs considering different return periods. For damage estimation, the processing included vectorization of lots, building use definition with Google Street View, classification of standard designs, and a field survey to validate those classes. In monetary value, this study calculated the effect of the construction of a reservoir for damage reduction, showing the potential to determine the effectiveness of measures adopted to mitigate flood impacts. In addition, for each simulated return period, exposure, hazard, and damage maps can be established, making it possible to perform a complete risk analysis.

Distribution and characteristics of microplastics in beach sand near the outlet of a major reservoir in north Mississippi, USA

Plastic debris both affects and is affected by the beaches it accumulates on. Most studies of microplastics (MPs) in beach sand are focused on coastal beaches or beaches of large lakes near population centers. Here, we assessed MP pollution at a sandy beach near the outlet of a major flood control reservoir (Sardis Lake) in a relatively unpopulated area in north Mississippi, USA, focusing on two prominent wrack zones and areas in-between. Putative MPs were isolated by density separation and matrix digestion, and then examined using stereomicroscopy, with a subset of samples additionally analyzed by µ-FTIR. MP abundance (particles/kg ± 1 standard error (SE), n = 15) averaged of 590 ± 360, with 950 ± 100 in the lower wrack zone, 540 ± 40 in the upper wrack zone, and 270 ± 30 in areas between; these differences were statistically significant (p < 0.01). The MPs generally had similar size and shape characteristics across sites. The majority were fibers (64%), followed by fragments (23%), beads (7%) and films (6%), with a slightly greater proportion of fibers in the wrack zones compared to areas in-between. The number of MPs rose dramatically with decreasing size. Beads were only found in the < 500 µm size fraction. Clear and blue were the predominant colors for all MPs. A total of 29 different types of polymers were detected, with more than half of the particles being composed of polyethylene and polyamide, followed by poly(methyl methacrylate), polyethylene terephthalate, polycarbonate, polypropylene, and others; although this distribution varied some depending on size fraction and location. Because there are no major wastewater discharges into Sardis Lake, the source of the MPs is likely degradation of carelessly discarded plastic, as well as atmospheric fallout. Overall, we found that MP concentrations were highest in the wrack zones and influenced by rates and duration of discharge from the reservoir. Thus, like coastal beaches, wrack zones on freshwater beaches along or downstream of reservoirs accumulate both macro- and micro-plastics and are prime locations for plastic cleanup. Finally, we show that MPs made from naturally weathered LDPE plastic film are prone to fragmentation during pretreatment procedures, which may result in its overestimation.