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Controlled in-stream flow manipulations are challenging but necessary to implement to assess the consequences of real-world flow alterations on aquatic ecosystems. We designed a double v-notch weir system, which was first prototype-tested in a laboratory flume and then in the field. The device diverted instantaneous flows proportionally in a robust way (e.g., 10% of flow in the stream main channel and 90% of flow into the diversion channel). We tested diversions systematically and evaluated how well flows matched our target flow-percentages. This is one of the first ecohydraulic structures designed and tested to experimentally manipulate environmental flows in small upland streams. [ABSTRACT FROM AUTHOR]

Sudden bursts in water distribution networks may lead to costly consequences. As pressure is one of the causes of such events, pressure management could reduce the probability of failure. In this work, a methodology is proposed to analyse the relationship between pipe breaks and water pressure by means of pressure-related indicators. The objective is to identify the most influential indicators for the probability of occurrence of pipe breaks. The methodology compares the cumulative distribution function (CDF) conditioned to breaks and 100 random sets of the same size sampled from the CDF of the indicator. The most influential indicators are related to the greatest number of rejected cases of the Kolmogorov-Smirnov test. Moment indicators and their calculation period emerge from sensitivity analyses. The methodology is applied to six sectors of Madrid (Spain) while two sectors are used for validation. Results show that the pressure range is the best indicator of breaks. [ABSTRACT FROM PUBLISHER]

The growing threat of abrupt and irreversible changes to the functioning of freshwater ecosystems compels robust measures of tipping point thresholds. To determine benthic cyanobacteria regime shifts in a potable water supply system in the tropical Andes, we conducted a whole ecosystem-scale experiment in which we systematically diverted 20 to 90% of streamflow and measured ecological responses. Benthic cyanobacteria greatly increased with a 60% flow reduction and this tipping point was related to water temperature and nitrate concentration increases, both known to boost algal productivity. We supplemented our experiment with a regional survey collecting > 1450 flow-benthic algal measurements at streams varying in water abstraction levels. We confirmed the tipping point flow value, albeit at a slightly lower threshold (40-50%). A global literature review broadly confirmed our results with a mean tipping point at 58% of flow reduction. Our study provides robust in situ demonstrations of regime shift thresholds in running waters with potentially strong implications for environmental flows management., (© 2022. The Author(s).)