WETLAND RESTORATION AND ITS EFFECTS ON THE HYDROLOGICAL CONDITIONS AND PROVISIONING ECOSYSTEM SERVICES -A MODEL-BASED CASE STUDY AT A HUNGARIAN LOWLAND CATCHMENT

Abstract

The alluvial character of the Great Hungarian Plain has long determined its land use. Human-environmental interactions and landscale patterns were characterised by adaptation to frequent floods and high water availability. Different socio-economical factors in the 18-19th centuries initiated major drainage works and river regulations. These works aimed to adjust hydrological conditions in the floodplains to meet the demands of a new land use approach. This focused on maximizing crop production as the dominant provisioning ecosystem service (ES) instead of the previous land use practice (e.g utilization a broader range of various ES by adaptition).
Over time, this new land use-water management strategy led to a trajectory of constrains: 1) Water demands of the agricultural landscape are restricted to a much narrower range than natural hydrological conditions, leading to damages during extremely dry or wet conditions; 2) Artificial drainage attempts to ensure this narrow range during wet periods in the protected former floodplain areas; 3) However, drainage increases water scarcity and drought damage during consecutive dry periods, which cannot be compensated by the irrigation system due to its limited capacity.
As a result of this outdated strategy and contemporary processes, Hungarian landscape management is facing a crisis. Climate and hydrological changes, the aging farmer community, agricultural sector profitability, alterations in the land use subsities, preferring greening and afforestation are among the leading factors of this crisis. These factors are likely to drive current land use conditions into a significantly altered riverine landscape scenario in the coming decades. Among the current environmental-economic-regulatory conditions, one of the most feasible alternative scenario focuses on water retention and the corresponding adaptive land use. However, the hydrological impacts of such alternative water management-land use on crop yield remain poorly understood.
We examined this by using hydrological simulations at a 272 km2 study site located next to the River Tisza. Here, the morphology of the heterogeneous terrain offers a remarkable semi-natural storage capacity as it encompasses a deep floodplain area.
We defined six different water governance-land use scenarios. First, three water management scenarios were defined and simulated: reference, excess water retention, and flood retention. Along these scenarios inland excess water (a specific type of flooding) hazard maps were used as an indicator for potentially reclaimable floodplains. Next, an alternative land use map was derived following the prevailing Hungarian landscape planning logic, considering factors such as present location and proportion of current agricultural croplands, grasslands, forests, settlement; soil conditions, water availability (agricultural suitability), and nature conservation status.
An integrated hydrological model was set up with the MIKE SHE software to depict spatio-temporal variations in water resources under present conditions (with an operational drainage system) and for all described alternative cases (without a drainage system). Simulated groundwater levels were a key output used to estimate changes in crop yields at selected pointwise locations. The results indicate significant potential for nature-based hydrological adaptation and co-benefits for provisioning ES.

Full text

WETLAND RESTORATION AND ITS EFFECTS ON THE HYDROLOGICAL CONDITIONS AND PROVISIONING
ECOSYSTEM SERVICES –A MODEL-BASED CASE STUDY AT A HUNGARIAN LOWLAND CATCHMENT
Zsolt Kozma1*, Tamás Ács1, Bence Decsi1,Máté Krisztián Kardos1,Dóra Hidy2,Mátyás Árvai3,4,Péter Kalicz5,Zoltán Kern6,7, Zsolt Pinke8
1Department of Sanitary and Environmental Engineering, Budapest University of Technology and Economics. E-mail: kozma.zsolt@emk.bme.hu;2MTA-MATE Agroecology Research Group, Department of Plant
Physiology and Plant Ecology, Hungarian University for Agriculture and Life Sciences; 3Institute for Soil Sciences, HUN-REN Centre for Agricultural Research; 4National Laboratory for Water Science and Water
Security, Institute for Soil Sciences, Centre for Agricultural Research; 5University of Sopron, Faculty of Forestry, Institute of Geomatics and Civil Engineering; 6Institute for Geological and Geochemical Research,
HUN-REN Research Centre for Astronomy and Earth Sciences; 7CSFK, MTA Centre of Excellence; 8Department of Physical Geography, Eötvös Loránd University;
Materials and methods
•The alluvial character of the Great Hungarian Plain has long determined its land use
•Major wetland and river regulations between the 18th and 20th centuries
led to a trajectory of constrains
•Agricultural production is influenced by floods, excess waters and droughts
•Contemporal Hungarian landscape management is facing a major crisis, worsened by climate change
•Combination of large scale water retention and adaptive land use seems to be the most feasible alternative scenario
•We examined such a Nature Based Solutions approach with hydrological simulations at a deep floodplain area along the Tisza River
Background, aims
The project FK20-134547 has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary.
The research reported in this poster is part of project no. BME-NVA-02, implemented with the support provided by the Ministry of Innovation and
Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021 funding scheme.
Land use scenario
Water management scenario
Reference (REF)
Excess Water Retention
(EWR)
EWR + Riverine
inundation (FLOOD)
Surface water coverage duration [%]
Ground-
water
depth at
well #2683
Present (CLC) Alternative (ALT)
Land
use Water
management
CLC REF
CLC FLOOD
ALT FLOOD
•For present conditions, the drainage network effectively reduces water coverage duration (CLC_EWR vs CLC_REF), but cannot
completly eliminate the excess water (CLC_REF)
•The extent and duration of water coverage can be controlled with stepwise water retention (Step 1: EWR; Step 2: FLOOD)
•Only water retention (CLC_EWR or CLC_FLOOD) would inhibit agricultural crop production in the low parts by water surplus
•Only aforestation (ALT_REF) without water retention would dry out the deep floodplain, also causing agricultural drought damage
•Finding the optimal proportion of afforestation and water retention could be facilitated with iterative modelling of various water
management-land use scenarios in the fashion introduced here
•As part of our research, these hydrological results are being assessed with crop yield modelling and tree growth estimates to
compare the provisioning ecosystem service performance of different scenarios
Results, conclusions
•3 water management * 2 land use variations
•Present land use and water management scenario (CLC_REF) was used for model calibraion: https://doi.org/10.3390/su151511700
•Excess water retention (EWR) = no drainage and no pumping of water surplus
•Riverine inundation (FLOOD) = EWR + a single release of ~33 million m3water from the flooding Tisza River into the area in 2003
•Alternative land use (ALT) follows the prevailing Hungarian landscape planning logic and is based on the CLC_FLOOD water coverage
duration results
•ALT: Half of the croplands were converted into wetlands (15% increase) or soft/hardwood forests (20% increase)
•Time period: 2000-2010
(incl. flood, droughts and excess water)
•Area: 243 km2, cell size: 50 m
•~20 m deep unconfined aquifer
•Looped channel network + pumps
•Fully coupled hydrological model:
MIKE SHE + MIKE RIVER
Six scenarios
Abstract