Changes in Water Age During Dry‐Down of a Non‐Perennial Stream

Water Resources Research, Journal Year: 2024, Volume and Issue: 60(1)

Published: Jan. 1, 2024

Abstract Non‐perennial streams, which lack year‐round flow, are widespread globally. Identifying the sources of water that sustain flow in non‐perennial streams is necessary to understand their potential impacts on downstream resources, and guide policy management. Here, we used isotopes (δ 18 O δ 2 H) two different modeling approaches investigate spatiotemporal dynamics young fractions ( F yw ) a stream network at Konza Prairie (KS, USA) during 2021 summer dry‐down season, as well over several years with varying hydrometeorological conditions. Using Bayesian model, found substantial amount : 39.1–62.6%) sustained flows headwaters catchment outlet year, while 2015–2022 contributions estimated using sinusoidal models indicated smaller amounts (15.3% ± 5.7). Both indicate releases highly sensitive hydrological conditions, shifting older dries. The shift age suggests away from rapid fracture toward slower matrix creates but localized surface presence late reflected annual outlet. proportion highlights vulnerability short‐term hydroclimatic change, reveals sensitivity longer‐term changes groundwater dynamics. Combined, this local may propagate through networks influence availability quality.

Language: Английский

---

Setting an environmental flow regime under climate change in a data-limited Mediterranean basin with temporary river

Journal of Hydrology Regional Studies, Journal Year: 2024, Volume and Issue: 52, P. 101698 - 101698

Published: Feb. 9, 2024

Catchment in Southern Italy. Mediterranean waterways are commonly non-perennial; they vulnerable to climate change (CC). Their management is particularly complex due limited data availability. This work aims develop a methodology for setting an Environmental Flow regime (E-Flows) temporary river (Locone, Italy) under availability and CC. As observed long-term time series of streamflow natural conditions were not available, the Soil Water Assessment Tool model (SWAT+) was applied simulate daily baseline period (1980–2010) future (2020–2050) based on projections, respectively. A specific workflow developed calibration focusing low flows. The hydrological characterized by means Indicators Hydrological Alteration (IHAs), whereas Range Variability Approach (RVA) define E-Flows. basin experiencing statistically significant increase air temperatures from 1971 2020, which also predicted continue future. Consequently, average annual monthly winter spring expected decrease. calibration, multi-objective evaluation, improved low-flow simulation. detected differences IHAs periods should be considered water when E-Flows rivers.

Language: Английский

---

Determination of River Ecological Flow Thresholds and Development of Early Warning Programs Based on Coupled Multiple Hydrological Methods

Water, Journal Year: 2024, Volume and Issue: 16(14), P. 1986 - 1986

Published: July 12, 2024

In order to safeguard the health of river ecosystems and maintain ecological balance, it is essential rationally allocate water resources. This study utilized continuous runoff data from 1967 2020 at Zhouqu Hydrological Station on Bailong River. Five hydrological methods, tailored characteristics cross-section, were employed. These methods included improved dynamic calculation method, NGPRP monthly frequency computation RVA Tennant method. Ecological flow calculations conducted determine flow, with analysis carried out through degree satisfaction, economic benefits, nonlinear fitting GCAS model. We established an threshold early warning program for this specific cross-section. values calculated using different each month year compared. The method resulted in small ranging 4.05 36.40 m3/s 7.65 22.94 m3/s, respectively, high satisfaction levels but not conducive ecologically sound development. contrast, yielded larger ranges 21.79–97.02 23.90–137.00 28.50–126.00 poor fulfillment benefits. thresholds determined model, 16.72 114.58 during abundant period 5.03 63.63 dry period. A three-level system was proposed based these thresholds, orange level indicating optimal sustainable development capacity Station. provides valuable insights into scientific management resources River Basin ensure security promote

Language: Английский

---

Development of an eco-hydrological distance index and improved environmental flow assessment by integrating ecological monitoring and hydrological modeling

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 969, P. 178961 - 178961

Published: Feb. 27, 2025

Achieving a good ecological status for rivers is primary goal under European water protection legislation, and establishing suitable environmental flows (e-flows) key to reach this objective. Typically, statistical hydrologic methods are used determine e-flows at the river basin district scale; however, these often overlook quality critical flow-ecology relationships, i.e., models linking streamflow responses. This study integrates monitoring data with address limitations of hydrological e-flow assessment. The new method developed in enables more precise definition thresholds development an eco-hydrological distance index (EHDI). EHDI indicates how closely river's flow aligns targets, taking into account catchment pressures. methodology involves: (i) balance simulation using distributed model that accounts human impacts, (ii) regression establish bad based on monitored data, (iii) EHDI, which compares actual identify where further abstraction should be restricted. application across 11,000 reaches Tuscany, (Italy) reveals many approach threshold summer. Instead only few deviate significantly from targets according mean annual flow. findings underscore statistical-hydrologic alone fail capture complex dynamics between regimes status, especially high pressure. In fact, when pressures significant, restoration natural would not enough achieve objectives.

Language: Английский

---

Modelling the impact of climate change on runoff and sediment yield in Mediterranean basins: the Carapelle case study (Apulia, Italy)

Frontiers in Water, Journal Year: 2025, Volume and Issue: 7

Published: March 13, 2025

Introduction This study analyzes the impact of climate change on streamflow and sediment yield in Carapelle basin, a Mediterranean watershed located Apulia Region Italy. Methods Three model projections (CMCC, MPI, EC-EARTH) under CMIP6 SSP2-4.5 scenario were bias-corrected evaluated using statistical measures to ensure enhanced fit with observed data. The Soil Water Assessment Tool (SWAT) was implemented simulate hydrology yield. calibrated validated measured load data from 2004–2011, demonstrating satisfactory performance for both parameters. Baseline conditions (2000–2020) compared future (2030–2050). Results Climate 2030-2050 indicated temperature increases up 1.3°C average annual rainfall decreases 38% baseline. These changes resulted reduced water across all models. CMCC projected highest reduction mean flow (67%), smaller reductions MPI (35%) EC-EARTH (7%). Correspondingly, 52.8% (CMCC), 41.7% (MPI), 18.1% (EC-EARTH). Despite these overall reductions, spatial analysis revealed that soil erosion remained critical (sediment >10 t ha −1 ) certain areas, particularly steep slopes wheat cultivation. Discussion Integrating considerations into management strategies is essential sustaining river basins conditions. Adaptation such as BMPs NBSs should be reduce mitigate impacts.

Language: Английский

---

Design of Ecological Flow (E-Flow) Considering Watershed Status Using Watershed and Physical Habitat Models

Water, Journal Year: 2023, Volume and Issue: 15(18), P. 3267 - 3267

Published: Sept. 14, 2023

Ecological flow (E-flow) determination is an essential component of stream management and the preservation aquatic ecosystems within a watershed. E-flow should be determined while considering overall status watershed, including hydrological cycle, hydraulic facility operation, ecology. The purpose this study to determine by watershed through coupled modeling with SWAT PHABSIM. was calibrated ensure reliability when coupling two models, using observed data that included streamflow dam inflows. calibration result showed averages R2, NSE, RMSE were 0.62, 0.57, 1.68 mm/day, respectively, showing satisfactory results. Flow duration analysis results performed apply discharge boundary conditions for Q185 (mid-range flows) Q275 (dry conditions) suitable simulate fish habitat. habitat suitability index derived survey applied PHABSIM estimate E-flow. estimated at 20.0 m3/s model compared notified instream Ministry Environment. demonstrate high level applicability approach between physical simulation models. Our attempt can utilized status.

Language: Английский

---

Use of Holistic Environmental Flow Assessment for the Alijanchay River, Azerbaijan

Water, Journal Year: 2024, Volume and Issue: 16(17), P. 2447 - 2447

Published: Aug. 29, 2024

Holistic environmental flow assessment includes evaluation of chemical, biological, hydrological, and morphological changes predicted from disrupting a river regime. Using available water chemistry together with biological hydrological surveys, we report assess flows the Alijanchay River, an important tributary Kura at four monitoring stations located in Azerbaijan. The river’s natural regime has changed significantly due to irrigation activities middle lower reaches further development is planned through construction new reservoirs. Our methodology based on results morphological, hydrobiological observations analysis physical chemical parameters river. Environmental was evaluated by six methods proposed literature, comparative shows that its value increased 13.6 27.1% annual volume, consistent pressure this surface supply. Water Quality Indices (WQI) show seasonal quality supply, impacting sustainable uses for drinking agriculture. Parameters most affected are turbidity, suspended solids, dissolved oxygen. Further degradation watershed Azerbaijan likely development. A more comprehensive holistic ecological can help support plan use River basin reserves, and, if resources provided other basins, elsewhere.

Language: Английский

---

Macroinvertebrate, algal and diatom assemblages respond differently to both drying and wetting transitions in non‐perennial streams

Freshwater Biology, Journal Year: 2024, Volume and Issue: 69(11), P. 1568 - 1582

Published: Sept. 20, 2024

Abstract Biological assemblages in streams are influenced by hydrological dynamics, particularly non‐perennial systems. Although there has been increasing attention on how drying impacts stream organisms, few studies have investigated specific characteristics of and subsequent wetting transitions influence biotic responses via resistance resilience traits. Here, we characterized hydrologic metrics, including those quantifying as well dry wet phases, alter diversity composition three aquatic southern California: benthic macroinvertebrates, soft‐bodied algae diatoms. We found that flow duration prior to sampling was correlated with variation macroinvertebrate algal assemblage composition. The richness diatom assemblages, however, were predominantly the start date sampling. Contrary other studies, phase did not or any assemblage. our study conducted within a region which each experienced comparable environmental conditions, no single metric all same way. hot‐summer Mediterranean climate California likely acts strong filter, taxa this relying adaptations survive recolonize following wetting. different metrics suggest greater events, for primary producers. As patterns continue change, understanding biodiversity could inform management actions enhance ecological communities streams. In particular, creation enhancement regimes natural timing phases sustain refuges support community persistence changing environment.

Language: Английский

---

Environmental flow assessment in transboundary rivers: Challenges and opportunities using big data - A Greek case study

E3S Web of Conferences, Journal Year: 2024, Volume and Issue: 585, P. 03005 - 03005

Published: Jan. 1, 2024

Environmental or ecological flow refers to the minimum needed sustain river- based ecosystems and their services. Evaluating environmental flows is of paramount importance, particularly in light rapid changes induced by climate change, anthropogenic pressures, continued damming river courses. The research aims evaluate four transboundary rivers Greece, namely Axios, Strymonas, Nestos Evros Rivers, using Tennant Tessman hydrological methods, assess compatibility with Greek national legislation. rivers’ runoff determined large-scale models applied at European scale, which simulate thousands basins simultaneously, generating extensive big data datasets. results demonstrate that legislation underestimates compared those derived from both methods. Furthermore, values method for winter months generally exhibit lower magnitudes obtained method, whereas during summer months, there appears be a convergence methodologies. proposed methodology can any within Union serve as significant roadmap further advancements assessment flow.

Language: Английский

---

Patch-scale habitat dynamics: three metrics to assess ecological impacts of frequent hydropeaking

Journal of Ecohydraulics, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 28

Published: Nov. 15, 2024

Human activities significantly alter natural river flows, impacting ecosystem functioning and biodiversity worldwide. Hydropeaking, resulting from intermittent on-demand hydropower generation, introduces sub-daily flow fluctuations exceeding variability. While the effects of single hydropeaking events are well-studied, cumulative impacts frequent requires further exploration. This study aims to develop metrics that captures changes in habitat dynamics at patch scale (i.e. individual micro-habitats within mosaic) due reoccurring hydropeaking. Using hydrodynamic simulations, we introduce three patch-scale quantify with high spatial (0.5 m) temporal (10 min) resolution: (M1) Habitat probability patches, assessing spatio-temporal diversity habitats; (M2) shifts evaluating persistence for sessile organisms (e.g. vegetation, invertebrates); (M3) Spatial habitats, indicating relocation affecting mobile species adult fish). eight hydro-morphological scenarios representing different levels anthropogenic modification morphology, demonstrate these effectively patch-scale. The results highlight ecological relevance their potentially utility management. By identifying areas susceptible impacts, may serve as tools mitigation, enabling more targeted spatially explicit management restoration.

Language: Английский

---