Linking hydrological response to forest dynamics in Mediterranean areas: a new experimental catchment in the Apennine Mountains, Tuscany, Italy

Author(s):  
Daniele Penna ◽  
Marco Borga ◽  
Elena Bresci ◽  
Giulio Castelli ◽  
Pietro Castellucci ◽  
...  

<p>The bi-directional ecohydrological interactions between forest dynamics and catchment hydrological response in Mediterranean forest ecosystems remain poorly conceptualized. Understanding the effect of tree water uptake and transpiration patterns on how catchments store and release water and, vice versa, on how catchment water availability affects tree physiological response is of paramount importance for forest and water resource management. This is crucial in the light of the predicted prolonged drought periods that will exacerbate the dry summer spells that characterize Mediterranean areas. In order to address these pressing issues, a new experimental mountain forested catchment for interdisciplinary ecohydrological research has been recently implemented in the Tuscan Apennines (Italy).</p><p> </p><p>The catchment size is 2 km<sup>2</sup> and elevation ranges from 650 to 1280 m a.s.l.. Forest covers more than 95% of the area, and the main tree species are beech and oak trees, with a much smaller proportion of conifers. Mean annual precipitation is around 1180 mm. Instrument installation is currently in progress and supported by two research projects (run in parallel in Italy and Luxembourg). By spring 2020, the catchment is expected to host the following equipment: one weather station plus one additional rain gauge, including a rainfall collector for isotope analysis; four stream gauges at different spatial scales (from a 2-ha headwater subcatchment to the catchment outlet) including continuous electrical conductivity measurements; three groundwater wells (ranging from 2 to 5 m depth) equipped with water level and electrical conductivity loggers; a network of soil moisture sensors at different depths; stemflow collectors; rain totalizers for manual throughfall measurements; a network of innovative multi-parametric sensors mounted on individual beech trees for continuous measurement (logging to cloud) of physiological and micro-meteorological parameters (sap flow, stem radial growth, canopy light transmission, stem wood temperature and humidity, 3D position over time, and air temperature and relative humidity).</p><p> </p><p>Preliminary data collected in 2019 show a marked seasonality of stream runoff, with low runoff coefficients in summer (<0.1), consistent with the high drainage of forested soils and large evapotranspiration fluxes. Stream electrical conductivity values increase from upstream to downstream sections, showing a consistent spatial variability among seasons and suggesting an increasingly relevance of subsurface flow for sustaining baseflow. Marked diel fluctuations in stream water levels during sunny summer days suggest a dominant control of tree transpiration on streamflow. Near-surface soil moisture spatial patterns at the hillslope scale show strong temporal stability. Future experimental activities will assess water pools used by beech trees along a hillslope. Planned tools and research include water stable isotopes, seasonal variations in canopy interception, stemflow, and throughfall as well as the spatio-temporal variability of soil moisture patterns at the plot, hillslope, and catchment scale.</p>

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Péter Hegedüs ◽  
Szabolcs Czigány ◽  
László Balatonyi ◽  
Ervin Pirkhoffer

AbstractFlash floods are one of the most significant natural hazards of today. Due to the complexity of flash flood triggering factors, to prevent or mitigate flood triggered losses, numeric model based flood forecasting models are capable tools to predict stream water levels. The main goal of the current research was to reproduce two flow peaks with the HEC-HMS rainfall-runoff model and test the model sensitivity for various input parameters. To obtain sufficient input data, we monitored soil depth, maximum infiltration rate, soil moisture content, rainfall, time of concentration and flow. To obtain input data, parameters were calculated, measured in the Sás Valley experimental watershed (SW Hungary) or optimized with the built in function of the HEC-HMS. Soil moisture was monitored in the 1.7 km2 pilot catchment over the period between September 2008 and September 2009. HEC-HMS had a good performance reproducing the two events, however simulated flow time series are highly influenced by the antecedent soil moisture, infiltration rate and canopy storage. Outflow modeled data were verified for two flood events (June 4, 2008 and July 9, 2009). The HEC-HMS was over-sensitive for input soil moisture and with increasing input rainfall and increasing outflow, larger simulation errors were observed.


Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1053
Author(s):  
Yuan Yao ◽  
Wei Qu ◽  
Jingxuan Lu ◽  
Hui Cheng ◽  
Zhiguo Pang ◽  
...  

The Coupled Model Intercomparison Project Phase 6 (CMIP6) provides more scenarios and reliable climate change results for improving the accuracy of future hydrological parameter change analysis. This study uses five CMIP6 global climate models (GCMs) to drive the variable infiltration capacity (VIC) model, and then simulates the hydrological response of the upper and middle Huaihe River Basin (UMHRB) under future shared socioeconomic pathway scenarios (SSPs). The results show that the five-GCM ensemble improves the simulation accuracy compared to a single model. The climate over the UMHRB likely becomes warmer. The general trend of future precipitation is projected to increase, and the increased rates are higher in spring and winter than in summer and autumn. Changes in annual evapotranspiration are basically consistent with precipitation, but seasonal evapotranspiration shows different changes (0–18%). The average annual runoff will increase in a wavelike manner, and the change patterns of runoff follow that of seasonal precipitation. Changes in soil moisture are not obvious, and the annual soil moisture increases slightly. In the intrayear process, soil moisture decreases slightly in autumn. The research results will enhance a more realistic understanding of the future hydrological response of the UMHRB and assist decision-makers in developing watershed flood risk-management measures and water and soil conservation plans.


Author(s):  
Jeremy A. Hartsock ◽  
Jessica Piercey ◽  
Melissa K. House ◽  
Dale H. Vitt

AbstractThe experimental Sandhill Wetland is the first permanent reclamation of a composite tailings deposit, and annual water quality monitoring is of specific interest for evaluating and predicting long-term reclamation performance. Here, we present water chemistry monitoring data obtained from Sandhill Wetland (years 2009–2019) and compare results to twelve natural reference wetlands and to environmental quality guidelines for Alberta surface waters. By comparing water quality at Sandhill Wetland and natural sites to established guidelines, we can begin to document the natural background water quality of wetlands in the region and examine if guideline exceedances are seen in natural undisturbed environments, or appear only at active reclamation sites. At Sandhill Wetland the dominant ions in near-surface water were bicarbonate, sulfate, chloride, sodium, calcium, and magnesium. Since the first growing season concentrations for these ions have increased annually, causing concurrent increases in electrical conductivity. In year 2019, water chemistry at Sandhill Wetland was most comparable to regional saline fens, systems that exhibit elevated electrical conductivity and high sodicity. Near-surface water at Sandhill Wetland exceeded water quality guidelines for three substances/properties (dissolved chloride, iron, and total alkalinity) in the most recent year of monitoring. The saline fen natural sites also exceeded water quality guidelines for the same chemical substances/properties, suggesting guideline exceedances are a norm for some natural wetland site types in the region. Of note, in each year of monitoring at Sandhill Wetland, dissolved organic compounds evaluated in sub- and near-surface water were below detection limits.


Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1061
Author(s):  
Thanh Thi Luong ◽  
Judith Pöschmann ◽  
Rico Kronenberg ◽  
Christian Bernhofer

Convective rainfall can cause dangerous flash floods within less than six hours. Thus, simple approaches are required for issuing quick warnings. The flash flood guidance (FFG) approach pre-calculates rainfall levels (thresholds) potentially causing critical water levels for a specific catchment. Afterwards, only rainfall and soil moisture information are required to issue warnings. This study applied the principle of FFG to the Wernersbach Catchment (Germany) with excellent data coverage using the BROOK90 water budget model. The rainfall thresholds were determined for durations of 1 to 24 h, by running BROOK90 in “inverse” mode, identifying rainfall values for each duration that led to exceedance of critical discharge (fixed value). After calibrating the model based on its runoff, we ran it in hourly mode with four precipitation types and various levels of initial soil moisture for the period 1996–2010. The rainfall threshold curves showed a very high probability of detection (POD) of 91% for the 40 extracted flash flood events in the study period, however, the false alarm rate (FAR) of 56% and the critical success index (CSI) of 42% should be improved in further studies. The proposed adjusted FFG approach has the potential to provide reliable support in flash flood forecasting.


1998 ◽  
Vol 78 (1) ◽  
pp. 115-126 ◽  
Author(s):  
R. L. Fleming ◽  
T. A. Black ◽  
R. S. Adams ◽  
R. J. Stathers

Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment


2007 ◽  
Vol 46 (10) ◽  
pp. 1587-1605 ◽  
Author(s):  
J-F. Miao ◽  
D. Chen ◽  
K. Borne

Abstract In this study, the performance of two advanced land surface models (LSMs; Noah LSM and Pleim–Xiu LSM) coupled with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5), version 3.7.2, in simulating the near-surface air temperature in the greater Göteborg area in Sweden is evaluated and compared using the GÖTE2001 field campaign data. Further, the effects of different planetary boundary layer schemes [Eta and Medium-Range Forecast (MRF) PBLs] for Noah LSM and soil moisture initialization approaches for Pleim–Xiu LSM are investigated. The investigation focuses on the evaluation and comparison of diurnal cycle intensity and maximum and minimum temperatures, as well as the urban heat island during the daytime and nighttime under the clear-sky and cloudy/rainy weather conditions for different experimental schemes. The results indicate that 1) there is an evident difference between Noah LSM and Pleim–Xiu LSM in simulating the near-surface air temperature, especially in the modeled urban heat island; 2) there is no evident difference in the model performance between the Eta PBL and MRF PBL coupled with the Noah LSM; and 3) soil moisture initialization is of crucial importance for model performance in the Pleim–Xiu LSM. In addition, owing to the recent release of MM5, version 3.7.3, some experiments done with version 3.7.2 were repeated to reveal the effects of the modifications in the Noah LSM and Pleim–Xiu LSM. The modification to longwave radiation parameterizations in Noah LSM significantly improves model performance while the adjustment of emissivity, one of the vegetation properties, affects Pleim–Xiu LSM performance to a larger extent. The study suggests that improvements both in Noah LSM physics and in Pleim–Xiu LSM initialization of soil moisture and parameterization of vegetation properties are important.


2021 ◽  
Author(s):  
Stefano Materia ◽  
Constantin Ardilouze ◽  
Chloé Prodhomme ◽  
Markus G. Donat ◽  
Marianna Benassi ◽  
...  

AbstractLand surface and atmosphere are interlocked by the hydrological and energy cycles and the effects of soil water-air coupling can modulate near-surface temperatures. In this work, three paired experiments were designed to evaluate impacts of different soil moisture initial and boundary conditions on summer temperatures in the Mediterranean transitional climate regime region. In this area, evapotranspiration is not limited by solar radiation, rather by soil moisture, which therefore controls the boundary layer variability. Extremely dry, extremely wet and averagely humid ground conditions are imposed to two global climate models at the beginning of the warm and dry season. Then, sensitivity experiments, where atmosphere is alternatively interactive with and forced by land surface, are launched. The initial soil state largely affects summer near-surface temperatures: dry soils contribute to warm the lower atmosphere and exacerbate heat extremes, while wet terrains suppress thermal peaks, and both effects last for several months. Land-atmosphere coupling proves to be a fundamental ingredient to modulate the boundary layer state, through the partition between latent and sensible heat fluxes. In the coupled runs, early season heat waves are sustained by interactive dry soils, which respond to hot weather conditions with increased evaporative demand, resulting in longer-lasting extreme temperatures. On the other hand, when wet conditions are prescribed across the season, the occurrence of hot days is suppressed. The land surface prescribed by climatological precipitation forcing causes a temperature drop throughout the months, due to sustained evaporation of surface soil water. Results have implications for seasonal forecasts on both rain-fed and irrigated continental regions in transitional climate zones.


2021 ◽  
pp. 1-48
Author(s):  
Olivia Martius ◽  
Kathrin Wehrli ◽  
Marco Rohrer

AbstractThree sets of model experiments are performed with the Community Earth System Model to study the role of soil moisture anomalies as a boundary forcing for the formation of upper-level Rossby wave patterns during Southern Hemisphere summer. In the experiments, soil moisture over Australia is set to ±1STD of an ERA-Interim reanalysis derived soil moisture reconstruction for the years 2009 to 2016 and 50 ensemble members are run. The local response is a positive heating anomaly in the dry simulations that results in a thermal low-like circulation anomaly with an anomalous surface low and upper-level anticyclone. Significant differences in convective rainfall over Australia are related to differences in convective instability and associated with changes in near surface moisture and moisture advection patterns. A circum-hemispheric flow response is identified both in the upper-level flow and in the surface storm tracks that overall resembles a positive Southern Annular Mode-like flow anomaly in the dry simulations. The structure of this atmospheric response strongly depends on the background flow. The results point to a modulation of the hemispheric flow response to the forcing over Australia by the El Niño Southern Oscillation. Significant changes of precipitation over the Maritime continent and South Africa are found and significant differences in the frequency of surface cyclones are present all along the storm tracks.


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