Connections between groundwater flow and transpiration partitioning

Science, Journal Year: 2016, Volume and Issue: 353(6297), P. 377 - 380

Published: July 22, 2016

Groundwater flow drives partitioning Soil evaporation and plant transpiration together contribute a substantial proportion of terrestrial freshwater fluxes. Land surface models are used to understand the these fluxes on continental scale; however, model outputs often inconsistent with stable isotope observations. Maxwell Condon incorporated dynamic groundwater into an integrated hydrologic simulation for entire United States. The showed that water table depth lateral strongly affect partitioning, thus explaining inconsistencies between observations models. Science , this issue p. 377

Language: Английский

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Forests and Water Yield: A Synthesis of Disturbance Effects on Streamflow and Snowpack in Western Coniferous Forests

Journal of Forestry, Journal Year: 2020, Volume and Issue: 118(2), P. 172 - 192

Published: Feb. 12, 2020

Abstract In coniferous western forests, recent widespread tree mortality provided opportunities to test the long-held theory that forest cover loss increases water yield. We reviewed 78 studies of hydrologic response standing-replacing (severe wildfire, harvest) or nonstand-replacing (drought, insects, low-severity wildfire) disturbances, and reassessed question: Does yield snowpack increase after disturbance? Collective results indicate postdisturbance streamflow may increase, not change, even decrease, illuminate factors help improve predictability disturbance. Contrary expectation reduces evapotranspiration, making more available as runoff, evapotranspiration sometimes increased—particularly following disturbance—because (a) increased evaporation resulting from higher subcanopy radiation, (b) transpiration rapid growth. Postdisturbance depends on vegetation structure, climate, topography, new hypotheses continue be formulated tested in this rapidly evolving discipline.

Language: Английский

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Snow Sublimation in Mountain Environments and Its Sensitivity to Forest Disturbance and Climate Warming

Water Resources Research, Journal Year: 2018, Volume and Issue: 54(2), P. 1191 - 1211

Published: Feb. 1, 2018

Abstract Snow sublimation is an important component of the snow mass balance, but spatial and temporal variability this process not well understood in mountain environments. This study combines a process‐based model (SnowModel) with eddy covariance (EC) measurements to investigate (1) spatio‐temporal simulated respect station observations, (2) contribution ablation snowpack, (3) sensitivity response bark beetle‐induced forest mortality climate warming across north‐central Colorado Rocky Mountains. EC‐based observations compared at stations dominated by surface canopy sublimation, blowing alpine areas was captured EC instrumentation. Water balance calculations provided validation watershed scale. Simulated area equivalent 28% winter precipitation on average, highest relative fluxes occurred during lowest years. from forested accounted for majority fluxes, highlighting importance sub‐canopy region. Simulations incorporating effects tree due bark‐beetle disturbance resulted 4% reduction areas. rates corresponding simulations remained unchanged or slightly increased, total losses decreased up 6% because covered duration.

Language: Английский

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Predicting Chronic Climate-Driven Disturbances and Their Mitigation

Trends in Ecology & Evolution, Journal Year: 2017, Volume and Issue: 33(1), P. 15 - 27

Published: Nov. 13, 2017

Language: Английский

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Simulating Fully‐Integrated Hydrological Dynamics in Complex Alpine Headwaters: Potential and Challenges

Water Resources Research, Journal Year: 2022, Volume and Issue: 58(4)

Published: March 11, 2022

Abstract Highly simplified approaches continue to underpin hydrological climate change impact assessments across the Earth's mountainous regions. Fully‐integrated surface‐subsurface models may hold far greater potential represent distinctive regimes of steep, geologically‐complex headwater catchments. However, their utility has not yet been tested a wide range settings. Here, an integrated model two adjacent calcareous Alpine headwaters that accounts for two‐dimensional surface flow, three‐dimensional (3D) variably‐saturated groundwater and evapotranspiration is presented. An energy balance‐based representation snow dynamics contributed model's high‐resolution forcing data, sophisticated 3D geological helped define parameterize its subsurface structure. In first known attempt calibrate catchment‐scale region automatically, numerous uncertain parameters were estimated. The salient features regime could ultimately be satisfactorily reproduced – over 11‐month evaluation period, Nash‐Sutcliffe efficiency simulated streamflow at main gauging station was 0.76. Spatio‐temporal visualization data responses further confirmed broad coherence. Presumably due unresolved local heterogeneity, closely replicating somewhat contrasting level signals observed near one another proved more elusive. Finally, we assessed impacts various simplifications assumptions are commonly employed in physically‐based modeling including use spatially uniform forcings, vertically limited domain, global products on key outputs, finding strongly affected performance many cases. Although certain outstanding challenges must overcome if uptake mountain regions around world increase, our work demonstrates feasibility benefits application such complex systems.

Language: Английский

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Hypoxia is common in temperate headwaters and driven by hydrological extremes

Ecological Indicators, Journal Year: 2023, Volume and Issue: 147, P. 109987 - 109987

Published: Feb. 10, 2023

Hypoxia, or dissolved oxygen (DO) at low enough levels to impair organisms, is a particularly useful indicator of the health freshwater ecosystems. However, due limited sampling in headwater networks, degree, distribution, and timing hypoxia events are not known across vast majority most river networks. We thus sought clarify extent networks through three years instrumentation 78 sites eight temperate, agricultural watersheds. observed broadly distributed hypoxia, occurring 4 % time 51 over 20 months. The was driven by mechanisms: storm events, drying, rewetting, with drying as common driver (55 all hypoxic event types). Drying induced severe smaller streams (Strahler orders ≤ 3), whereas preferentially larger 3–5). A large diversity DO trajectories towards depended on hydrologic type, subsequent expected differences mortality profiles sensitive species. Predictive models showed vulnerable were small slope, during hot, discharge periods. Despite variation among there remarkable similarity rate drawdown (ca. 1 mg O2 L−1 d−1). This may be rule-of-thumb for managers, we hypothesize that it either signal increasing lateral inflow water downstream demand. Overall, posit likely feature often goes undetected. Headwater become more under increasingly dry conditions associated climate resource management changes, important implications biological communities biogeochemical processes.

Language: Английский

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In ecoregions across western USA streamflow increases during post-wildfire recovery

Environmental Research Letters, Journal Year: 2017, Volume and Issue: 13(1), P. 014010 - 014010

Published: Nov. 22, 2017

Continued growth of the human population on Earth will increase pressure already stressed terrestrial water resources required for drinking water, agriculture, and industry. This stress demands improved understanding critical controls resource availability, particularly in water-limited regions. Mechanistic predictions future availability are needed because non-stationary conditions exist form changing climatic conditions, land management paradigms, ecological disturbance regimes. While historically disturbances have been small could be neglected relative to effects, evidence is accumulating that disturbances, wildfire, can regional availability. However, wildfire hydrologic impacts typically estimated locally at spatial scales, via disparate measurement methods analysis techniques, outside context climate change projections. Consequently, importance driven versus streamflow remains unknown across western USA. Here we show considering modeling significantly improves model predictions. Mixed effects attributed 2%−14% long-term annual effects. The this wildfire-linked predicted change-induced reductions ranged from 20%−370% decrease occur by 2050. rate post-wildfire vegetation recovery proportion watershed area burned controlled effect. Our results demonstrate large areas USA affected subject greater structural uncertainty than previously thought. These suggest streamflows may underestimated increased prevalence hydrologically relevant such as wildfire.

Language: Английский

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Disturbance Hydrology: Preparing for an Increasingly Disturbed Future

Water Resources Research, Journal Year: 2017, Volume and Issue: 53(12), P. 10007 - 10016

Published: Oct. 24, 2017

Abstract This special issue is the result of several fruitful conference sessions on disturbance hydrology, which started at 2013 AGU Fall Meeting in San Francisco and have continued every year since. The stimulating presentations discussions surrounding those focused understanding both disruption hydrologic functioning following discrete disturbances, as well subsequent recovery or change within affected watershed system. Whereas some disturbances are directly linked to anthropogenic activities, such resource extraction, contributions this focus primarily with indirect less pronounced human involvement, bark‐beetle infestation, wildfire, other natural hazards. However, activities enhancing severity frequency these seemingly thereby contributing acute problems Major research challenges for our increasingly disturbed planet include lack continuous pre postdisturbance monitoring, impacts that vary spatially temporally based environmental hydroclimatic conditions, preponderance overlapping compounding sequences. In addition, a conceptual framework characterizing commonalities differences among still its infancy. introduction issue, we advance fusion concepts terminology from ecology hydrology begin filling gap. We briefly explore preliminary approaches comparing different their impacts, provides starting point further dialogue progress.

Language: Английский

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100 Years of Progress in Hydrology

Meteorological Monographs, Journal Year: 2018, Volume and Issue: 59, P. 25.1 - 25.51

Published: Jan. 1, 2018

The focus of this chapter is progress in hydrology for the last 100 years. During period, we have seen a marked transition from practical engineering to fundamental developments hydrologic science, including contributions Earth system science. first three sections review advances theory, observations, and prediction. Building on foundation, growth global hydrology, land–atmosphere interactions coupling, ecohydrology, water management are discussed, as well brief summary emerging challenges future directions. Although attempts be comprehensive, offers greater coverage surface hydrometeorology readers American Meteorological Society (AMS) monograph.

Language: Английский

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Climate-driven disturbances in the San Juan River sub-basin of the Colorado River

Hydrology and earth system sciences, Journal Year: 2018, Volume and Issue: 22(1), P. 709 - 725

Published: Jan. 26, 2018

Abstract. Accelerated climate change and associated forest disturbances in the southwestern USA are anticipated to have substantial impacts on regional water resources. Few studies quantified impact of both land cover balances basin scale, none scale. In this work, we evaluate a headwater Colorado River, San Juan River watershed, using robustly calibrated (Nash–Sutcliffe efficiency 0.76) hydrologic model run with updated formulations that improve estimates evapotranspiration for semi-arid regions. Our results show future will streamflow implications resource management. findings contradiction conventional thinking reduce increase streamflow. study, annual average under coupled climate–disturbance scenarios is at least 6–11 % lower than those accounting alone; forested zones basin, 15–21 lower. The monthly signals altered point an emergent pattern related changes forests disturbed systems. Exacerbated reductions mean low flows disturbance indicate high risk availability systems basin. These also explicit representation required modeling efforts consider

Language: Английский

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