Catchworks: A Historical Water-Distribution System on Mountain Meadows in Central Slovakia

Abstract

Water meadows or flooded meadows are known from many European countries. A historical irrigation system—catchworks—was identified in only one locality in Slovakia. This article brings a methodical approach to the identification of catchworks on mountain slopes. The main aim was to delineate catchworks using terrain and land use geospatial data intended to supplement existing data on catchworks from the field survey. The identification of shallow and narrow channels in the field is difficult, and their detection in a digital terrain model (DTM) and orthomosaic photos is also challenging. A detailed DTM elaborated from laser scanning data was not available. Therefore, we employed break lines of a Triangulated Irregular Network (TIN) model created by EUROSENSE Ltd. 2017, Bratislava, Slovakia. to determine microtopographic features on mountain slopes. Orthomosaics with adjusted red (R) green (G) and blue (B) band thresholds (digital numbers) in a time sequence of 16 years (2002–2018) and the Normalized Green-Red Difference Index (NGRDI) (2018) determined vital herbaceous vegetation and higher biomass. In both cases, the vegetation inside wet functional catchworks was differently coloured from the surroundings. In the case of dry catchworks, the identification relied only on microtopography features. The length of catchworks mapped in the field (1939.12 m; 2013) was supplied with potential catchworks detected from geospatial data (2877.18; 2018) and their total length in the study area increased above 59.74% (4816.30 m). Real and potential catchworks predominantly occupied historical grassland (meadows and pastures) (1952–1957) (4430.31; 91.99%). This result corresponds with the findings of foreign studies referring that catchworks on mountain slopes were related to livestock activities. They are important elements of sustainable land use with a water retention function in traditional agricultural landscapes.