The Hydrological Open Air Laboratory (HOAL) in Petzenkirchen: a hypotheses driven observatory

Abstract

Abstract. Hydrological observatories bear a lot of resemblance to the more traditional research catchment concept but tend to differ in providing more long term facilities that transcend the lifetime of individual projects, are more strongly geared towards performing interdisciplinary research, and are often designed as networks to assist in performing collaborative science. This paper illustrates how the experimental and monitoring setup of an observatory, the 66 ha Hydrological Open Air Laboratory (HOAL) in Petzenkirchen, Lower Austria, has been established in a way that allows meaningful hypothesis testing. The overarching science questions guided site selection, identifying dissertation topics and the base monitoring. The specific hypotheses guided the dedicated monitoring and sampling, individual experiments, and repeated experiments with controlled boundary conditions. The purpose of the HOAL is to advance the understanding of water related flow and transport processes involving sediments, nutrients and microbes in small catchments. The HOAL catchment is ideally suited for this purpose, because it features a range of different runoff generation processes (surface runoff, springs, tile drains, wetlands), the nutrient inputs are known, and it is convenient from a logistic point of view as all instruments can be connected to the power grid and a high speed glassfibre Local Area Network. The multitude of runoff generation mechanisms in the catchment provide a genuine laboratory where hypotheses of flow and transport can be tested, either by controlled experiments or by contrasting sub-regions of different characteristics. This diversity also ensures that the HOAL is representative of a range of catchments around the world and the specific process findings from the HOAL are applicable to a variety of agricultural catchment settings. The HOAL is operated jointly by the Vienna University of Technology and the Federal Agency for Water Management and takes advantage of the Vienna Doctoral Programme on Water Resource Systems funded by the Austrian Science Funds. The paper presents the science strategy of the setup of the observatory, discusses the implementation of the HOAL, gives examples of the hypothesis testing and summarises the lessons learned. The paper concludes with an outlook on future developments.

Using Cosmic-Ray Neutron Probes to Monitor Landscape Scale Soil Water Content in Mixed Land Use Agricultural Systems

“…The average annual temperature is 9.5 ∘ C. The research station is located in an undulating agricultural landscape, characterized by Cambisols (56%), Planosols (21%), Anthrosols (17%), Gleysols (6%), and Histosols (<1%). Infiltration capacities tend to be medium to low, water storage capacities tend to be high, and shrinking cracks may occur in summer due to high clay contents (see Table A1 and Figure 4 in [21]). The main crops are winter wheat, barley, maize, and rape.…”

“…The study site, Hydrological Open Air Laboratory (HOAL) [21], is a cooperation project between the Federal Agency for Water Management (BAW Petzenkirchen) and the Technical University Vienna (TU Vienna), is located in Petzenkirchen, about 100 km west of Vienna and receives an annual average 823 mm of rainfall mostly between April and September. The average annual temperature is 9.5 ∘ C. The research station is located in an undulating agricultural landscape, characterized by Cambisols (56%), Planosols (21%), Anthrosols (17%), Gleysols (6%), and Histosols (<1%).…”

“…Table 1 summarizes the 2014 planting, soil cultivation, and harvest dates of 11 of the 12 land use parcels within the study area. For full details of the study site, available datasets, overarching research questions, and specific hypotheses, see [21].…”

Real time flood forecasting in the Upper Danube basin

“…For example, Scherrer and Naef (2003) identified Hortonian overland flow, saturation excess flow, lateral subsurface flow and vertical subsurface flow on a 60 m² hillslope. Blöschl et al (2015) identified infiltration excess overland flow, re-infiltration of overland flow, saturation excess runoff from wetlands, tile drainage flow, shallow aquifer seepage flow and groundwater discharge from springs in the 66 ha Hydrological Open Air Laboratory (HOAL) in Lower Austria, and Rogger et al (2012) classified runoff generation mechanisms by the hydrogeological characteristics through extensive field explorations in a 73 km² catchment. In addition to the catchment properties, climatological and meteorological properties will also affect the dominant processes (e.g., Gutknecht, 1993Gutknecht, , 1994Merz and Blöschl, 2003;Sui and Koehler, 2001).…”

Technical Note: Monitoring streamflow generation processes at Cape Fear

“…Field data captured therein have enabled investigations on the role of bedrock topography on subsurface storm flow (Freer et al, 2002), and have led to the formulation of the fill and spill hypothesis (Tromp-van Meerveld and McDonnell, 2006a, b;Klaus et al, 2013). Further, the catchment-scale Hydrological Open Air Laboratory (HOAL) in Lower Austria is a 66 ha labora-10 tory (Blöschl et al, 2015), which is an extremely rich testbed for the comprehension of water flow and transport processes.…”