Improving Indicators of Hydrological Alteration in Regulated and Complex Water Resources Systems: A Case Study in the Duero River Basin

Assessing the health of hydrological systems is vital for the conservation of river ecosystems. The indicators of hydrologic alteration are among the most widely used parameters. They have been traditionally assessed at the scale of river reaches. However, the use of such indicators at the basin scale is relevant for water resource management since there is an urgent need to meet environmental objectives to mitigate the effects of present and future climatic conditions. This work proposes a methodology to estimate the indicators of hydrological alteration at the basin scale in regulated systems based on simulations with a water allocation model. The methodology is illustrated through a case study in the Iberian Peninsula (the Duero River basin), where different minimum flow scenarios were defined, assessing their effects on both the hydrological alteration and the demand guarantees. The results indicate that it is possible to improve the hydrological status of some subsystems of the basin without affecting the water demand supplies. Thus, the methodology presented in this work will help decision makers to optimize water management while improving the hydrological status of the river basins.

Quantitative assessment of hydrological alteration over multiple periods caused by human activities at the Jingjiang Three Outlets, China

The Jingjang Three Outlets (JTO) play a major role in the water-sediment transport from the Yangtze River to Dongting Lake. The hydrological regimes at the JTO (Songzi, Taiping, and Ouchi) had been changed due to the Jingjiang Cutoffs (JC), the Gezhou Dam (GD), and the Three Gorges Dam (TGD). Based on hydrological data from 1955 to 2019, the variation trend in annual streamflow was detected using three techniques, and the hydrological alteration was assessed with the Range of Variability Approach. Conclusions are as follows: (1) the inflection points consistent with human activities and the time series were divided into periods of P1 (1955–1971), P2 (1972–1985), P3 (1986–2002), and P4 (2003–2019); (2) human activities made a greater contribution to streamflow change than climate change; (3) the hydrological alteration degree caused by the JC, GD, and TGD projects were 56%, 47%, and 52% at the Songzi outlet; 57%, 41%, and 57% at the Taiping outlet; and 57%, 41%, and 57% at the Ouchi outlet; and (4) the ability of division from the Yangtze River to Dongting Lake is weakening and the hydrological regimes at the JTO are deteriorating due to the JC, GD, and TGD, resulting in negative impacts on the biotic composition, structure, and function of riparian ecosystems. This study provides useful insight for ecosystem protection under hydrological alteration. HIGHLIGHT Quantitative assessment of hydrological alteration over multiple periods. Differentiated the influence of cutoffs projects and dam construction on hydrological alteration. Discussed the negative impacts of hydrological alteration on ecosystems and the countermeasures for future.

Temporal and Spatial changes in Crop Patterns, Use of inputs and Hydrological Alteration in the case of Fogera floodplain, Ethiopia

BauckgroundMore than half of the world's population consumes rice. The area under modern rice varieties has expanded, the use of chemical fertilizers and pesticides has increased in various countries. The hydrology of wetlands are also influenced by its chemical and physical characteristics. Hence, this research focused on temporal and spatial changes in crop patterns, input usage, and hydrological change in Fogera floodplain, with the objectives: a. what are the spatial and temporal trends in crops production pattern? b. What inputs have been used in the past and present to produce rice and other crops? c. What looks like the hydrological alteration of the area? The primary data was gathered through a questionnaire, focus group discussions, interviews, and field observations. Secondary data from Landsat imageries, SWAT input data, water flow, normalized difference vegetation index, and hydrological alteration of the site were collected. To analyze data, tables, graphs, and charts percentage, mean, and correlation were used. ResultNDVI results indicated that rice crop is growing while other variables are decreasing. artificial inputs are currently used but before the introduction of rice were not. Recession farming activities have also diminished wetland. Annual average water flow and rainfall have been trending upward. Flow of water with Nitrogen and Phosphorous has a negative correlation, with Pearson's values -0.069 and -0.072, respectively whereas the value 0.242 indicates that nitrogen and phosphorus have a positive relationship. ConclusionIn conclusion, these extended and intensification of farming practices have an impact on the biodiversity of fauna and flora of the area.

Risk of increased hydrological alteration due to penetration of intermittent renewable energy generation

<p>The penetration of intermittent renewable energy sources (RES) such as solar PV and wind is rapidly growing in many countries. Due to the RES intermittency, it is becoming increasingly difficult to manage the balance between energy generation and demand at any time. In this context, it is necessary to use other energy generation technologies, such as hydropower, a controllable renewable source that may already be available as a means to provide energy balance. Hydropower, through hydropeaking, is considered a flexible solution to this challenge as it can quickly help manage the fluctuations in the generation-demand balance due to the highly RES intermittency. Hydropeaking plants usually supply energy at maximum capacity during on-peak periods, whereas they run at low power output during off-peak periods. However, this operating scheme leads to heavy hydrological alteration downstream of the hydropower plants because of short-term fluctuations in turbined flows motivated by the integration of intermittent RES. In this work, an integrated and spatially distributed river-basin and energy system co-simulation model is used to evaluate the hydrological alteration produced by varying penetration levels of intermittent RES in Ghana's national power system. Results show that the spatial and temporal distribution of hydrological alteration, correlated with intermittent RES penetration levels, varies according to the hydropower plants' location within the power system and the intermittent renewable resources seasonality throughout the year.</p>