Flooding is a prevalent and growing problem involving significant economic losses worldwide. Traditional flood mitigation measures are based on the use of levees, dams, dredging, and river channelization, which can distort the perception of risk, leading to a false sense of security that can induce an increase in the occupation of flood-prone areas. An undisturbed watershed and its fluvial system provide regulating services that contribute to flood mitigation. However, anthropogenic activities can degrade and diminish such services, impacting the magnitude of floods by changing the runoff patterns, erosion, sedimentation, channel conveyance capacity, and floodplain connectivity. Restoration and natural flood management (NFM) seek to recover and improve their watershed regulation services. The bibliographic review performed here aimed to assess the degradation of the natural regulation services of watersheds, which allowed us to identify significant alterations to runoff and streamflow. Also, the review studies of NMF allowed us to identify the restoration actions oriented to recover or enhance the flow regulation capacity of catchments and their fluvial systems. A current challenge is to accumulate more empirical evidence for the effectiveness of such flood mitigation solutions. Currently, the results for large catchments have been obtained mainly by the application of hydrologic and hydraulic models. Also, the adequacy of the different NFM actions to catchments with different physiographic and climatological settings needs to be addressed.

The estimation and review of discharge flow rates in hydraulic works is a fundamental problem in water management. In the case of dams with large regulating capacity, in order to estimate return periods of discharge flow rates from the spillways, it becomes necessary to consider both peak flow and volume of the incoming floods. In this paper, the results of the validation for several methods of assessing design floods for spillways of dams with a large flood control capacity are presented; the validation is performed by comparing the maximum outflows (or the maximum levels reached in the reservoir) obtained from the routing of the design floods with those obtained from the routing of the historical annual maximum floods. The basin of Malpaso Dam, Mexico, is used as the case study. Editor D. Koutsoyiannis Citation Domínguez, M.R. and Arganis, J.M.L., 2012. Validation of methods to estimate design discharge flow rates for dam spillways with large regulating capacity. Hydrological Sciences Journal, 57 (3), 460–478.

The objective of the present study was to develop a genetic algorithm capable of establishing optimal operating policies for monthly extractions from the three main reservoirs of the Cutzamala System, which supply drinking water to the Mexico City metropolitan area. In previous studies, annual water extraction defined with an annual Z curve in terms of the total water storage in the reservoirs on November 1 was optimized using genetic algorithms. In this study, a percentage of total annual extraction for each reservoir was also optimized, but monthly water extractions were adjusted too, when the water level fell outside the upper or lower limits of guide curves stablished for each reservoir. The capabilities of the genetic algorithms combined with a detailed simulation of reservoirs operation were used to optimize the levels of the guide curves and also to optimize the adjusted monthly programed extractions as linear functions of the difference between the actual storage level at the beginning of each month and the corresponding level of the guide curves. Therefore, 90 parameters were established: four to define the Z curve, two to establish the percentage assigned to each reservoir, 72 to establish the monthly levels of the guide curves and 12 to define the parameters of the linear functions used to adjust the monthly programed extractions when the actual water level exceeds the limits of the guide curves. For each alternative of the 90 parameters, a detailed simulation is done using the last 20 years of hydrological data on the inflow of water to the three main reservoirs, including the net contributions of five diversion dams, and the objective function sought to maximize water delivery to the treatment plant, while penalizing possible spills and deficits in the system is evaluated. The optimal policies found in this research resulted in smaller spills than those that occurred during the historical operation of the reservoir system. Therefore, the optimal monthly operating decisions required for each reservoir are provided by the genetic algorithm.

Pumped-storage hydroelectric plants are an alternative to adapting the energy generation regimen to that of the demand, especially considering that the generation of intermittent clean energy provided by solar and wind power will cause greater differences between these two regimes. In this research, an optimal operation policy is determined through a simulation tool that allows the annual benefits under the energy arbitration service (purchase–sale) to be estimated, considering the variations of the energy price in Mexico. A case study is proposed in the Zimapán hydroelectric facility, where reservoir operation at the hourly level is simulated with records for a period of 3 years, considering historical values. The results establish that this type of pumped storage power plant obtains greater benefits by generating electrical energy during 8 h of high demand and pumping for more than 11 continuous hours in times of low demand. With this configuration, the PHES consumes 82.33 GWh/year more energy than it produces, and the energy generated is 210.83 GWh/year; however, when considering the energy arbitration service, a net income of more than USD 3.25 million per year is identified, which represents a 123.52% increase for the annual energy purchase.