Wüstebach long-term experimental catchment
The Wüstebach long-term experimental catchment
The Wüstebach catchment is located in the German low mountain ranges within the borders of the Eifel National Park (50°30’ N, 6° 19’ E) near the German-Belgian border.
The catchment area is 38.5 ha.
The catchment belongs to the temperate oceanic climate region. The climate can be characterized as humid with a mean annual temperature of 8.2 °C and a mean annual precipitation of 1310 mm/yr from 1991 to 2013 (data from meteorological station Kalterherberg (German Weather Service)). Precipitation tends to be higher in winter than in summer.
The geology is dominated by Devonian shales with occasional sandstone inclusions, which is covered by a periglacial solifluction layer of about 1–2 m thickness. Cambisols and Planosols have developed on the hillslopes, whereas Gleysols and Histosols (half-bogs) have formed under the influence of groundwater in the valley. The main soil texture is silty clay loam with a medium to high fraction of coarse material and the litter layer has a thickness between 0.5 and 14 cm (mean: 5.8 cm).
The elevation of the catchment ranges from 595 to 628 m a.s.l. The average slope is 3.6% and the maximum slope is 10.4%.
Norway spruce (Picea abis L.) and Sitka spruce (Picea sitchensis) are the dominating vegetation within the catchment with an average density of 370 trees/ha. Currently, forest management in the Eifel National Park promotes the natural regeneration of near-natural beech forest from spruce monoculture forest that was originally established solely for timber production. For the Wüstebach catchment, a spatially explicit and coherent clear-felling area was selected that will significantly influence the biogeochemical parameters and functioning of the forest ecosystem. During late summer/early autumn of 2013, trees were almost completely removed in an area of 9 ha, which corresponds to approximately 23% of the total catchment area. The deforestation measure focused on the wettest part of the catchment near the main Wüstebach stream, and the affected soils were mainly Gleysols and some adjacent Cambisols.
Context of investigation
The catchment is part of the TERENO Lower Rhine Valley-Eifel observatory. The deforestation experiment is an example for such an integrated monitoring and analysis approach. The expected strong effects will facilitate the detection of associated system changes in response to the imposed disturbance and will provide a unique insight into the recovery and regeneration of forest systems.
In the framework of TERENO, the Wüstebach catchment has been instrumented between 2007 and 2010 with a large variety of measurement equipment to obtain information about hydrological, chemical, and meteorological states and fluxes [Bogena et al., 2015]. The basic infrastructure and monitoring consists of:
- Atmospheric processes: The main meteorological measurements are concentrated around a 38 m high tower that was installed in the northwestern part of the catchment. At 12 m above the forest canopy, measurements of the 3D wind vector, temperature, humidity and CO2 concentration are taken at a frequency of 20 Hz. Wind direction and speed is measured using a Campbell Scientific CSAT3 sonic anemometer. Gas concentrations are determined using a LiCor Li-7500 open-path gas analyzer, installed 15 cm north of the anemometer. In September 2013, a second EC station was installed in the center of the clear-felling area at a height of 2.5 m above the surface to minimize the footprint area. The equipment of this EC station is identical to the equipment installed at the meteorological tower. Three raingauges and 150 totalisators (weekly sampling) are installed to monitor spatial rainfall patterns.
- Soil moisture: The wireless soil moisture sensor network SoilNet enables the measurement of catchment scale soil water content pattern dynamics in the Wüstebach catchment. The SoilNet in Wüstebach consists of 150 sensor units with 600 ECH2O EC-5 and 300 ECH2O 5TE sensors (Decagon Devices, Pullman, WA, USA) buried at 5 cm, 20 cm, and 50 cm. Two sensors at each depth measure soil moisture content every 15 minutes. In addition to the in-situ soil moisture monitoring, a CRS-1000 cosmic-ray soil moisture neutron probe (CRNP, Hydroinnova LLC, Albuquerque, NM, USA) is installed in the center of the Wüstebach catchment. The CRNP non-invasively measures the integral soil moisture state of the catchment by counting fast neutrons in hourly interval (measurement footprint has a radius of ~200 m).
- Soil respiration: Two measurement transects were installed in the Wüstebach catchment in 2006 to measure soil respiration at 35 locations with a separation of 10 m. At each location, PVC collars (Ø 20 cm) were inserted 5-8 cm into the forest floor. This set-up was extended with an additional 49 measurement points in 2008 in the center of the deforestation area in a grid configuration. Soil respiration was measured weekly at each transect location using a closed dynamic chamber system (LI-8100-101, Licor Biosciences Ltd), along with soil temperature measurements at 5 and 11 cm depth and soil moisture measurements (integral from 0 to 15 cm).
- Soil chemistry: Due to the strong link between water and biogeochemical nutrient fluxes, it is expected that the deforestation will alter the soil chemical status. Therefore, soil chemical properties before and after deforestation have been determined and evaluated using a series of soil sampling campaigns (see Bogena et al., 2015 for more details).
- Water balance: Six lysimeters (surface area: 1.0 m²; depth: 1.5 m) were installed in the Wüstebach catchment to determine precipitation, actual evapotranspiration (resolution of 1 mm), and the change in soil water storage. The amount of water leaving the bottom of the lysimeter (leachate) is also determined (resolution of 0.1 mm, 1 minute interval). All lysimeters were filled with undisturbed soil monoliths from the Wüstebach site in a way that avoids compaction and other disturbances. Vegetation on the lysimeters is natural grassland without management (e.g. no fertilization and cutting). The lower boundary condition of each lysimeter is controlled using parallel suction pipes that were installed at the end of the filling procedure.
- Runoff: Discharge is measured at three runoff stations (15 min frequency), all equipped with a combination of a V-notch weir for low flow measurements and a Parshall flume to measure normal to high flows.
- Water quality: Weekly grab samples for water chemical analyses are collected at several locations along the Wüstebach stream. In addition, weekly samples are taken from the main tributaries of the Wüstebach stream and from the stream in the reference catchment. Furthermore, multi-probes (YSI 6820, YSI Inc., USA) that measure water temperature, pH and electrical conductivity every 15 min and auto-samplers (AWS 2002, Ecotech, Germany) with an hourly sampling interval have been installed at all runoff gauging stations to capture fast changes in water chemistry during discharge events. Finally, water temperature, pH, redox potential and electrical conductivity are also measured manually during the weekly sampling campaigns using field instruments (WTW, Xylem Inc., USA). All samples collected for analysis of water chemistry are filtered in the laboratory (0.45 µm) before major anions and cations are measured using IC (Cl-, NO3-, SO4-, NH4+, PO42-) and ICP-OES (Al3+, Fetot, Ca2+, Mg2+, Na+, K+). Concentrations of ammonium and phosphate are typically very low and near or below the detection limit (0.06 and 0.08 mg/L) and thus not presented here. Spectral UV absorption as an indicator of organic carbon is measured as SAK254 on a spectrophotometer (Varian), and dissolved organic carbon (DOC) concentration is determined as non-purgeable organic carbon (Shimadzu TOC-VCPN) on the filtered sample
- Groundwater: 9 piezometers were installed within the catchment (mainly in riperian zone) where groundwater level are continuously monitored.
- Vegetation: Two sites were selected to measure sapflow fluxes as a proxy for tree transpiration. The first site is located near the Wüstebach River and is influenced by groundwater fluctuations. The second site is located at the hillslope and is unaffected by groundwater. At each site, three trees were instrumented with sapflow sensors to infer transpiration fluxes of the spruce trees. Sap flow is measured using improved Granier sensors with four needles (Ecomatik SF-L sensors; Ecomatik, 2005).
- Stable Isotopes: Weekly precipitation samples for isotopic analysis are collected from a wet deposition collector at the TERENO meteorological station Schöneseiffen (620 m a.s.l., 3.5 km northeast of the Wüstebach catchment). The samples are collected in 2.3 liter HDPE bottles, which are cooled in-situ by a standard refrigerator. The isotopic analysis is carried out using Isotope-Ratio Mass Spectrometry (IRMS) with high-temperature pyrolysis Oxygen and hydrogen stable isotope values are reported as delta values (18O, 2H) against Vienna Standard Mean Ocean Water (VSMOW) on the SMOW scale using laboratory standards calibrated against international standards (VSMOW, SLAP2 and GISP) for calibration.
In order to better understand the hydrological processes, several modelling efforts have been undertaken at the Wüstebach catchment:
Parflow-CLM: ParFlow-CLM is a grid based, fully integrated groundwater flow model that solves the Richards’ equation in 3D. The coupled land surface model CLM simulates the land surface energy mass balance components and thus PCLM has a more detailed physical description than HGS and MSHE that use potential evapotranspiration as model input. PCLM simulates 2D surface flow by solving the kinematic wave equation. The vertical discretization of the Wüstebach model in ParFlow-CLM consists of 2.5 cm thick layers from terrain to bedrock. The lateral discretization of the structured grid is 10 m. Please refer to Fang et al. (2015) and (2016) for more information.
HydroGeoSphere: HydroGeoSphere is a fully integrated hydrological model that solves the 3D Richards’ equation for subsurface flow with the numerical finite difference method. Surface and channel flow are expressed by 2D and 1D diffusion wave approximations of the Saint Venant equation, respectively. The model domain of the Wüstebach is discretized with a triangulated network containing 805 nodes which represents an average resolution of 25 m. Additional 164 nodes are added to the riparian zone for a refined description of the channel topography. Please refer to Cornelissen et al. (2013) for more information.
MIKE-SHE: MIKE-SHE is a grid based hydrological model which comprises coupled modules that describe 3D groundwater flow (finite difference), 1D unsaturated flow (Richards’equation), 2D overland flow and river routing (Table 3). The model is not considered fully integrated; however full coupling between the modules is performed at each time step. For the Wüstebach model setup the unsaturated zone is discretized with an increasing thickness of the numerical layers with depth (5 cm to 20 cm). The lateral discretization of the structured grid is 10 m. Please refer to Koch et al. (2016) for more information.
TRANSEP: The conceptual rainfall-runoff transfer function hydrograph separation model TRANSEP was used to determine of stream water transit time distributions. Please refer to Stockinger et al. (2014) for more information.
Links to project webpages
- Altdorf, D., C. v. Hebel, N. Borchard, J v. d. Kruk, H.R. Bogena, H. Vereecken and J.A. Huisman (2016): Potential of catchment-wide soil water content mapping using electromagnetic induction in a forest ecosystem. Submitted to Environmental Earth Science.
- Andreasen, M., K.H. Jensen, M. Zreda, D. Desilets, H. Bogena and M.C. Looms (2016): Modeling cosmic-ray neutron field measurements. Water Resour. Res. 52, doi:10.1002/2015WR018236.
- Baatz R., H. Bogena, H.-J. Hendricks Franssen, J.A. Huisman, C. Montzka and H. Vereecken (2015). Development of an empirical vegetation correction for soil water content quantification using cosmic-ray probes. Water Resour. Res., 51, DOI: 10.1002/2014WR016443
- Baatz, R., Hendricks Franssen, H.-J., Han, X., Hoar, T., Bogena, H. and Vereecken, H. (2016). Evaluating the value of a network of cosmic-ray probes for improving land surface modeling. Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-432.
- Bogena, H., E. Borg, A. Brauer, P. Dietrich, I. Hajnsek, I. Heinrich, R. Kiese, R. Kunkel, H. Kunstmann, B. Merz, E. Priesack, T. Pütz, H.P. Schmid, U. Wollschläger, H. Vereecken and S. Zacharias (2016): TERENO: German network of terrestrial environmental observatories. Journal of large-scale research facilities 2, A52, http://dx.doi.org/10.17815/jlsrf-2-98.
- Bogena, H.R., J.A. Huisman, R. Baatz, R., H.-J. Hendricks Franssen and H. Vereecken (2013): Accuracy of the cosmic-ray soil water content probe in humid forest ecosystems: The worst case scenario. Water Resour. Res., 49 (9): 5778-5791, DOI: 10.1002/wrcr.20463.
- Bogena, H.R., M. Herbst, J.A. Huisman, U. Rosenbaum, A. Weuthen and H. Vereecken (2010): Potential of wireless sensor networks for measuring soil water content variability. Vadose Zone J., 9 (4): 1002-1013, doi:10.2136/vzj2009.0173.
- Bogena, H.R., R. Bol, N. Borchard, N. Brüggemann, B. Diekkrüger, C. Drüe, J. Groh, N. Gottselig, S.J. Huisman, A. Lücke, A. Missong, B. Neuwirth, T. Pütz, M. Schmidt, M. Stockinger, W. Tappe, L. Weihermüller, I. Wiekenkamp and H. Vereecken (2015): A terrestrial observatory approach for the integrated investigation of the effects of deforestation on water, energy, and matter fluxes. Science China: Earth Sciences 58(1): 61-75, doi: 10.1007/s11430-014-4911-7.
- Bol, R., A. Lücke, W. Tappe, S. Kummer, M. Krause, S. Weigand, T. Pütz and H. Vereecken (2015): Spatio-temporal Variations of Dissolved Organic Matter in a German Forested Mountainous Headwater Catchment. Vadose Zone J. 14(4), doi: 10.2136/vzj2015.01.0005.
- Cornelissen, T., B. Diekkrueger and H. Bogena (2013): Using HydroGeoSphere in a forested catchment: How does spatial resolution influence the simulation of spatio-temporal soil moisture variability? Procedia Environmental Sciences, 19: 198-207, doi: 10.1016/j.proenv.2013.06.022.
- Cornelissen, T., B. Diekkrüger and H.R. Bogena (2016): Transferring small scale parameterization to improve mesoscale catchment modelling. Water 8(5), 202, doi:10.3390/w8050202.
- Fang, Z., H.R. Bogena, S. Kollet, J. Koch and H. Vereecken (2015): Spatio-temporal validation of long-term 3D hydrological simulations of a forested catchment using empirical orthogonal functions and wavelet coherence analysis. J. Hydrol., doi:10.1016/j.jhydrol.2015.08.011.
- Fang, Z., H.R. Bogena, S. Kollet, J. Koch and H. Vereecken (2016): Scale dependent parameterization of soil hydraulic conductivity in the 3D simulation of hydrological processes in a forested headwater catchment. J. Hydrol. 536: 365–375, doi:10.1016/j.jhydrol.2016.03.020
- Gottselig N. and I. Wiekenkamp,, L. Weihermüller, N. Brüggemann, A.E. Berns, H.R. Bogena, N. Borchard, E. Klumpp, A. Lücke, A. Missong, T. Pütz, H. Vereecken, J.A. Huisman and R. Bol (2016): Soil biogeochemistry in a forested headwater catchment – A three dimensional view. Submitted to Journal of Environmental Quality Dataset.
- Graf, A., H. R. Bogena, C. Drüe, H. Hardelauf, T. Pütz, G. Heinemann, Vereecken, H., 2014: Spatiotemporal relations between water budget components and soil water content in a forested tributary catchment, Water Resour. Res., 50, 4837–4857, http://doi.org/doi:10.1002/ 2013WR014516.
- Iwema, J., R. Rosolem, R. Baatz, T. Wagener and H. R. Bogena (2015): Investigating temporal field sampling strategies for site-specific calibration of three soil moisture – neutron intensity parameterisation methods. Hydrol. Earth Syst. Sci. 19: 3203–3216, doi: 10.5194/hess-19-3203-2015.
- Koch, J., S. Stisen, Z. Fang, H.R. Bogena, T. Cornelissen, B. Diekkrüger and S. Kollet (2016): Inter-comparison of three distributed hydrological models with respect to the seasonal variability of soil moisture patterns at a small forested catchment. J. Hydrol. 533: 234-249, doi:10.1016/j.jhydrol.2015.12.002.
- Korres, W., T.G. Reichenau, P. Fiener, C.N. Koyama, H.R. Bogena, T. Cornelissen, R. Baatz, M. Herbst, B. Diekkrüger, H. Vereecken, and K. Schneider (2015): Spatio-temporal soil moisture patterns - a meta-analysis using plot to catchment scale data. J. Hydrol. 520: 934-946, doi:10.1016/j.jhydrol.2014.11.042.
- Missong, A., Bol, R., Willbold, S., Siemens, J. and Klumpp, E. (2016): Phosphorus forms in forest soil colloids as revealed by liquid-state 31P-NMR. J. Plant Nutr. Soil Sci., 179: 159–167. doi: 10.1002/jpln.201500119.
- Qu, W., H.R. Bogena., J.A. Huisman, J. Vanderborght, M. Schuh, E. Priesack and H. Vereecken (2015): Predicting sub-grid variability of soil water content from basic soil information. Geophys.Res.Lett. 42: 789–796, doi:10.1002/2014GL062496.
- Rosenbaum, U., H.R. Bogena, M. Herbst, J.A. Huisman, T.J. Peterson, A. Weuthen, A. Western and Vereecken, H. (2012): Seasonal and event dynamics of spatial soil moisture patterns at the small catchment scale. Water Resour. Res., 48(10), W10544, doi:10.1029/2011WR011518.
- Shurong, L., M. Herbst, R. Bol, N. Gottselig, T. Pütz, D. Weymann, I. Wiekenkamp, H. Vereecken and N. Brüggemann (2016): The contribution of hydroxylamine content to spatial variability of N2O formation in soil of a Norway spruce forest, Geochimica et Cosmochimica Acta 178: 76-86, doi.org/10.1016/j.gca.2016.01.026.
- Stockinger, M., H. Bogena, A. Lücke, B. Diekkrüger, M. Weiler and H. Vereecken (2014): Seasonal Soil Moisture Patterns Control Transit Time Distributions in a Forested Headwater Catchment. Water Resour. Res., 50, doi:10.1002/2013WR014815.
- Stockinger, M.P., A. Lücke, J.J. McDonnell, B. Diekkrüger, H. Vereecken and H.R. Bogena (2015): Interception effects on stable isotope driven streamwater transit time estimates. Geophys. Res. Lett., 42: 5299–5308, doi:10.1002/ 2015GL064622.
- Stockinger, M.P., H.R. Bogena, A. Lücke, B. Diekkrüger, T. Cornelissen and H. Vereecken (2016): Tracer sampling frequency influences estimates of young water fraction and streamwater transit time distribution. J. Hydrol., doi:10.1016/j.jhydrol.2016.08.007
- Weigand, S., R. Bol, B. Reichert, A. Graf, I. Wiekenkamp, M. Stockinger, A. Lücke, W. Tappe, H. Bogena, T. Pütz, W. Amelung, H. Vereecken (2016): Spatiotemporal dependency of dissolved organic carbon to nitrate in stream- and groundwater of a humid forested catchment – a wavelet transform coherence analysis. Submitted to Vadose Zone J.
- Wiekenkamp, I., J.A. Huisman, H. Bogena, A. Graf, H. Lin, C. Drue and H. Vereecken (2016): Changes in Spatiotemporal Patterns of Hydrological Response after Partial Deforestation. Submitted to J. Hydrol.
- Wiekenkamp, I., J.A. Huisman, H. Bogena, H. Lin and H. Vereecken (2016): Spatial and Temporal Occurrence of Preferential Flow in a Forested Headwater Catchment. J. Hydrol. 534: 139-149, doi:10.1016/j.jhydrol.2015.12.050.
- Zacharias, S., H. Bogena, L. Samaniego, M. Mauder, R. Fuß, T. Pütz, M. Frenzel, M. Schwank, --C. Baessler, K. Butterbach-Bahl, O. Bens, E. Borg, A. Brauer, P. Dietrich, I. Hajnsek, G. Helle, R. Kiese, H. Kunstmann, S. Klotz, J.C. Munch, H. Papen, E. Priesack, E., H.P. Schmid, R. Steinbrecher, U. Rosenbaum, G. Teutsch and H. Vereecken (2011): A network of terrestrial environmental observatories in Germany. Vadose Zone J., 10 (3): 955-973.