Historic maps as a data source for socio-hydrology: a case study of the Lake Balaton wetland system, Hungary

Abstract

Abstract. Socio-hydrology is the science of human influence on hydrology and the influence of the water cycle on human social systems. This newly emerging discipline inherently involves a historic perspective, often focusing on timescales of several centuries. While data on human history is typically available for this time frame, gathering information on the hydrological situation during such a period can prove difficult: measured hydrological data for such long periods are rare, while models and secondary data sets from geomorphology, pedology or archaeology are typically not accurate enough over such a short time. In the first part of this study, the use of historic maps in hydrology is reviewed. Major breakthroughs were the acceptance of historic map content as valid data, the use of preserved features for investigating situations earlier than the map, and the onset of digital georeferencing and data integration. Historic maps can be primary quantitative sources of hydro-geomorphological information, they can provide a context for point-based measurements over larger areas, and they can deliver time series for a better understanding of change scenarios.In the second part, a case study is presented: water level fluctuations of Lake Balaton were reconstructed from maps, levelling logs and other documents. An 18th century map system of the whole 5700 km 2 catchment was georeferenced, integrated with two 19th century map systems, and wetlands, forests and open water digitized. Changes in wetland area were compared with lake water level changes in a 220 yr time series. Historic maps show that the water level of the lake was closer to present-day levels than expected, and that wetland loss pre-dates drainage of the lake.The present and future role of historic maps is discussed. Historic hydrological data has to be treated with caution: while it is possible to learn form the past, the assumption that future changes will be like past changes does not always hold. Nevertheless, old maps are relatively accessible data sets and the knowledge base for using them is rapidly growing, and it can be expected that long-term time series will be established by integrating georeferenced map systems over large areas.In the Appendix, a step-by-step guide to using historic maps in hydrology is given, starting from finding a map, through georeferencing and processing the map to publication of the results.

Socio-hydrological modelling: a review asking "why, what and how?"

“…Hydrological modelling often suffers from data unavailability , but significant work has been carried out in recent years on prediction in ungauged basins (Hrachowitz et al, 2013;Wagener and Montanari, 2011) to reduce this, and so perhaps the potential multi-disciplinary data scarcity issues in socio-hydrology could borrow and adapt some techniques. Papers discussing solutions for a lack of data in a socio-hydrological context are also already appearing (Zlinszky and Timár, 2013). Data scarcity can heavily influence the modelling technique used (Odongo et al, 2014): lumped conceptual models tend to have "more modest.…”

“…To this end, Di Baldassarre et al (2015b) point out that the use of stylised models can help to guide researchers towards the data that are needed, setting off an iterative process of model-data-theory development. With regard to unconventional data, Troy et al (2015a) have propounded the use of proxy data in socio-hydrology where data do not exist, and Zlinszky and Timár (2013) have investigated the potential for an unconventional data source for socio-hydrology: historical maps.…”

Distribution and composition of Mg-calcite and dolomite in the water and sediments of Lake Balaton

“…Thus, the composition of the Mg-calcite that precipitates from the water and is deposited into the sediments of Lake Balaton is apparently related to significant variations of the water level, caused by the alternation of humid and dry climatic periods. However, in the last three centuries anthropogenic influences often overprinted the natural fluctuations of the water level (Zlinszky and Timár 2013).…”

Desiccation frequency drives local invasions of non-native gibel carp (Carassius gibelio) in the catchment of a large, shallow lake (Lake Balaton, Hungary)

“…Afterwards, water level regulation works started by constructing Sió Canal, which reduced the water level of the lake. As a consequence, the connected wetlands mostly disappeared, became astatic or were converted into fish ponds (Korponai et al, 2010;Zlinszky and Tímár, 2013). The shore zone itself has also been drastically altered, by the destruction of the natural ecotone (reed belts) and construction of artificial shore ramparts (e.g.…”