Rehabilitation in the mining context refers to restoring the natural characteristics such as land stability, vegetation, soil functions, biodiversity and hydrological cycle. The main aim of mine rehabilitation is to construct environmentally sustainable landforms and to restore their ecosystem services, either to a site specific stable equilibrium or ideally to its previous state. The objective of this work is to build a predictive and decision making tool using hypothetical modelling to simulate water fluxes for two different scenarios in terms of different soil cover depth including vegetation (grass). Hypothetical hydrological modelling was performed using the HYDRUS-1D with one-dimension water flow modelling based on the Richards equation and hydraulic functions of van Genuchten-Mualem model. The soil and coal hydraulic parameters were derived from laboratory tests using the extended evaporation method. Water flux modelling was performed for 2021 using the climatic data from Latrobe Valley (Victoria, Australia) meteorological station, where the coal and soil samples were collected. Two scenarios were selected which varied in the depth of soil cover and coal layer, both with grass vegetation on top of the soil columns. The first scenario (S1) had 50 cm of soil cover, while the second scenario (S2) had 100 cm of soil cover on top of coal material, respectively. Modelling results revealed that soil water content and fluxes were directly reflecting the precipitation pattern and the most limiting factor in downward water flow was the low permeability of the coal layer. The hydraulic parameters for coal show large water retention capacity at very low hydraulic conductivity. The shallower soil cover in the S1 scenario resulted in higher soil water content during the period of intense rainfall and resulted in larger and faster initiation of surface runoff. The thicker soil cover layer resulted in larger infiltration rate and root water uptake which was however limited when the soil was fully saturated in both scenarios. Interestingly, very similar bottom flux in both scenarios even with two different coal layer depth (i.e., 30 cm vs 80 cm) were recorded. Water balance results indicate increase in potential of storing water in the S1 scenario which has a thicker coal layer due to its high water retention capacity. However, at this point it is not clear to what extent stored water from coal can be available for plants. Beside valuable research insights in terms of soil cover design, hypothetical modelling will assist in preventing experimental design flaws and providing a more efficient, robust controlled experiment performed in a next study phase.

How to cite: Filipović, V. and Baumgartl, T.: Hydrological performance of soil and vegetation covers impact in mine rehabilitation: results of a preliminary modelling study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4348, https://doi.org/10.5194/egusphere-egu23-4348, 2023.

Forests are critically influenced by game animals since the browsing and peeling by these animals has a detrimental effect on forests by affecting a broad range of processes in forest ecosystems. Further, plants that are browsed by herbivorous game animals show stress reactions which can lead to a change in plant species composition and in belowground interactions between roots and soil microorganisms. On the other hand, a high game population density leads to high nutrient and carbon (C) inputs via excrement and, in case of feeding, via fodder inputs. These inputs can have positive effects on plant nutrition and growth as well as soil organic C build-up. While previous studies have focused on various topics related to the effects of game animals on forest ecosystems, an overarching understanding of soil-plant-wildlife interactions and feedback reactions is still missing. In this study, we aim at tackling this short-coming and elucidating the effect of long-term enhanced game population density on soil physical, chemical, and microbial properties. The study site includes different forest types located in the vicinity of Vienna, Austria, and consists of a fenced area with high game animal population density and a directly adjacent, open forest area with lower animal density, serving as a control. Soil samples were taken from three depths (0-10 cm, 10-20 cm, 20-50 cm) from ten sub-sites differing in plant species composition and underbrush density. In the laboratory, we analyzed soil density, particle size distribution, pH, electric conductivity, total C and N, microbial biomass C and N, plant-available nutrients, and root density to study the effect of a high density of game animals (wild boars, deer) in the study area. The results gained in this study will serve as a scientific basis for a subsequent, long-term research and monitoring strategy. Here, we present results from the first sampling campaign and discuss implications of environmental impacts of wildlife animals on a larger scale.

How to cite: Inselsbacher, E., Gerzabek, H., Nopp-Mayr, U., and Gerzabek, M.: Effects of long-term enhanced game population density on soil physical, chemical, and microbiological properties, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7488, https://doi.org/10.5194/egusphere-egu23-7488, 2023.

The tropical mountainous environments of the Northern-western provinces of Rwanda in Africa are often referred to as the breadbasket of the country and are also densely populated. This high demographic pressure is associated with significant land management practices. In particular, agricultural practice of terracing has been promoted as soil and water conservation measure on the steep hillslopes of the region. However, the region is also landslide prone and the  potential effect of terracing on landslides occurrence has never been considered in the land management strategy. In this work, we assess this  potential effect through the analysis of more than 4000 recent landslides that were triggered by intense rainfall events. Exploring the role of slope, lithology, regional landslide susceptibility patterns and the types of terraces (typology, age), we show that, overall, terracing increases the odds of landsliding when compared to non-terraced hillslopes. Although the terraces are implemented as soil and water conservation measures in the region, we find that they result into higher hillslope hazard.

How to cite: Sibomana, P., Vanmaercke, M., Nahayo, D., Depicker, A., Tychon, B., Hubert, A., Rukundo, E., and Dewitte, O.: Potential effect of agricultural terraces on landslide occurrence: the tropical mountains of Rwanda, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9126, https://doi.org/10.5194/egusphere-egu23-9126, 2023.

During the last few decades significant amount of agricultural land in Latvia have been abandoned and overgrown, due to various factors. It is considered that abandonment is strongly influenced by socioeconomic and political factors, however, soil quality should be taken into consideration, as it plays a very important role in the development of vegetation. The aim of the research is to clarify spatial relationship of soil properties with different land use change scenarios.
The study was conducted in the polygon (310 ha) characterized by slightly undulated topography in the southeast part of Latvia, where over the last 60 years, abandonment of agricultural land and overgrowth with forest has been observed.
For the spatial assessment of land use change, aerial photo materials between 1954 and 2014 were digitized, where three types of land use were determined: arable land, grassland and forest. From 1954 till 2014 land use in the study area has changed significantly, therefore several scenarios were distinguished: a) arable land → forest; b) grassland → forest; c) arable land → grassland; d) grassland → grassland. In the study area 36 soil profiles were established, samples were collected and physical and chemical analyses (soil texture (sand, silt, clay (%), pH_KCl, total carbon (%), total nitrogen (%), exchangeable cations (Ca²⁺, Mg²⁺, K⁺, Fe³⁺, Al³⁺) (cmol(+) kg^-1)) according to standard methods were conducted in the laboratory. To estimate statistically significant (p<0.05) differences between land use scenarios and soil properties was used One-Way ANOVA.
The study results shows that the area covered by forest increased from 11% to 62%, between 1954 and 2014, but arable land decreased from 33% to 0,1% and grassland area decreased by 20%. In 2014 agricultural lands are mainly overgrown with Alnus incana (48.6%), Salix caprea (19%) and Betula pendula (14%), as well with Populus tremula and Picea abies. Statistical analyses showed significant differences of soil textural classes: content of sand and silt fraction, pH_KCl value, and exchangeable cations (Ca²⁺, Al³⁺) between former arable land that changed to forest and arable land that changed to grassland. Arable land overgrows faster in areas of poorer soil and lighter soil textural classes, in contrast longer agricultural activity was found in areas, characterized by relatively heavier soil textural classes. Soil was more acidic and concentration of Al³⁺ was significantly higher in areas that have been overgrown by trees. 
Statistical analysis revealed that soil texture, acidity and nutrient availability significantly influence further development of land, either area will be transformed to forest or kept as grassland. Although, overgrowth is considered as reasonable land use option of abandoned agricultural lands, preliminary results showed that investigated marginal lands are suitable for farming. Further study will be conducted in a wider region for deeper understanding of mechanisms responsible for land use changes.

How to cite: Afanasjeva, K., Kasparinskis, R., and Nikodemus, O.: Spatial relationships between soil properties and land use change after agricultural land abandonment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9891, https://doi.org/10.5194/egusphere-egu23-9891, 2023.

Predictions of the fate of coastal wetlands under the effects of sea-level rise (SLR) vary widely due to uncertainties on environmental variables, but also due to unavoidable simplifications in the models. Here, we present a simplified domain ecogeomorphic model that includes all relevant hydrodynamic, sedimentation and vegetation dynamics mechanisms that affect wetland evolution, it does not require detailed information and it is efficient enough computationally to allow the simulation of long time periods. We test this framework and apply it in different settings typically found in coastal wetlands around the world, comprising different geomorphic configurations, vegetation types, sediment characteristics and tidal regimes. Most of the wetland settings analysed are unable to cope with the high SLR rates expected by the end of the century, in agreement with results using paleo-records during periods of high SLR rates.

How to cite: Rodriguez, J., Saco, P., Breda, A., Sandi, S., and Saintilan, N.: Predicting the fate of coastal wetlands using a simplified domain ecogeomorphic model., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10518, https://doi.org/10.5194/egusphere-egu23-10518, 2023.

Soil erosion is a balance between forces acting to detach and transport sediment and those resisting, such as soil cohesion or protection of vegetation cover. The amount of eroded particles is proportional to the acting forces, but the feedback, as is widely acknowledged, has a non-linear behaviour. Moreover, most of the erosion is concentrated in the strongest events, as evidenced by many authors.
Here, in a long-term simulation, we investigate the occurrence of the size of the erosion events in a vineyard catchment area. We analysed around 700 rainfall events over 20 years  from two climate series (historical 1985-2005, and and future 2040-2060), and four contrasted land use and management scenarios.
The results confirmed that the erosion is driven by a limited number of strong events with an increment in future series due to an increase in frequency of the more severe rainfall events. We observed that: 1) Size of erosion events VS return time exhibit different logarithmic trends in each LU scenario; 2) Long-term erosion series show that the few major erosion phases are due to a limited number of events, the most severe; 3) The concentration of erosion events towards the highest values is more pronounced in intensified landscape indicating more reactive erosion than in protected landscapes.
This suggests that controlling the state of intensification of a landscape (i.e. intensified or preserved) can mitigate soil erosion even if climate change tends to increase erosion rates.

How to cite: Ciampalini, R., Pastor, A., Huard, F., Follain, S., Licciardello, F., Crabit, A., and Raclot, D.: Modelling soil erosion focusing on event-size occurrences under global change in a vineyard catchment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11301, https://doi.org/10.5194/egusphere-egu23-11301, 2023.

Plateau pika (Ochotona curzoniae) is a small, common burrowing herbivore with average 150 g, native to grassland in the Asia, especially to alpine meadows in the Qinghai-Tibetan Plateau. Termed as bioturbator herbivores, this animal can create extensive soil disturbance through digging and burrowing activities. In the process of disturbing the soil, these animals break the soil surface layer, increasing water infiltration, soil moisture, and the capture of organic matter, which leads to change in soil ecological processes. This small burrowing herbivore can shape alpine meadows, even contributes to alpine meadow degradation because its density can range up to 300 individuals per hectare. Consequently, plateau pika is generally considered as a pest in China and extensive control efforts have been conducted to eradicate it. However, several studies have argued that plateau pika is a keystone species for alpine meadow ecosystem. To date, no consensus about the role of plateau pika in alpine meadow ecosystem has emerged among policy makers, professionals and herders, and more studies are needed to examine the impact of plateau pika on soil process. Therefore, take plateau pika as an example, our study focuses on accurately evaluating the service functions of the alpine grassland ecosystem including productivity, soil conservation, and C sequestration under the bioturbation by small burrowing herbivore.

How to cite: Pang, X., Xu, X., and Wang, Y.: Soil disturbance: Responses of soil carbon to plateau pika bioturbation in alpine grasslands on the Qinghai Tibetan Plateau, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13424, https://doi.org/10.5194/egusphere-egu23-13424, 2023.

Rainfed agriculture is conducted on 80% of the world's arable land and provides 60% of the world's food, therefore playing an important role in ensuring food security for a growing population. Climate change impacts are predicted to be harmful for rainfed agriculture all over the world, which will face future yield reductions of up to 30%, so more attention should be given to the efficient use of agricultural water in agricultural production, especially under rainfed conditions. Intercropping is a traditional sustainable planting system having advantages of increased production and improved yield stability, which is widely valued and has attracted increasing interest as a strategy to deal with climate change. Clarify the water consumption process of the intercropping system, especially the complementary and competition mechanism of soil water between species, is necessary for optimizing the field management and improving the water use efficiency of the intercropping system. The Loess Plateau is a typical rainfed farming area in northern China, the limitation of water resources and soil erosion are two major problems for efficient agricultural production. Therefore, we focuses on water consumption process of the intercropping system on the Loess Plateau, and the research results can provide theoretical support for the healthy and sustainable development of agriculture in rainfed area.

How to cite: Ma, L.: A strategy to deal with climate change: Intercropping system has attracted increasing interest., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14554, https://doi.org/10.5194/egusphere-egu23-14554, 2023.

Microclimatic variations in semi-arid ecosystems can cause topographic asymmetry over geologic time scales due to uneven distribution of incoming solar radiation as a function of slope aspect. This phenomenon has long been recognized in geomorphology and has been studied primarily in catchments with high spatial heterogeneity in climate forcing and underlying lithology. Due to fluctuations in prevailing climate and lithological differences in the studied catchments, the formation age and size of the catchments add another level of complexity and uncertainty. Due to their small size, uniform lithology, well-constrained initial morphology, and relatively young age, cinder cones are natural laboratories for better understanding the eco-hydro-geomorphic evolution caused by nonlinear interactions between vegetation, climate, and soil. The Sandal Divlit cinder cone located in the Kula volcanic field, western Turkey, is an inactive volcano and formed in the last stage of volcanism in the region. The climax vegetation in the primary succession following the volcanic eruption can be seen on north-facing slopes with trees. North-facing slopes have deeper soils than south-facing slopes, which have sparsely herbaceous plants and shrubs and thin, weakly developed soils. Airborne-LiDAR surveys and the digital elevation models having 5 m and 12.5 m spatial resolution were used to analyze the geomorphic descriptors and canopy structure of the cone as a function of aspect. In the summer and winter seasons, the surface temperatures of the cone were measured using a thermal-imaging drone. The results show that north-facing slopes are much cooler and have less evaporative demand than south-facing ones. As a result of denser vegetation attributed to relatively more available soil moisture, they are steeper than south-facing ones due to better erosion protection. Despite its young age (<30 ka), the cone has developed topographic asymmetry and is imprinted with the signature of aspect-related vegetation difference. This finding is further evaluated and with the results of landscape evolution models to assess the role of microclimate due to vegetation on the development of asymmetric geomorphological features.

This study has been produced benefiting from the 2232 International Fellowship for Outstanding Researchers Program of the Scientific and Technological Research Council of Turkey (TUBITAK) through grant 118C329. The financial support received from TUBITAK does not indicate that the content of the publication is approved in a scientific sense by TUBITAK.

How to cite: Yetemen, O., Avcioglu, A., Ozcan, O., Simsek, I., Kolbuken, M., Yeo, I.-Y., Chun, K. P., Gorum, T., and Sen, O. L.: Influence of Hillslope Aspect on a Cinder Cone Evolution: The Sandal Divlit example, Kula, Turkey, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15745, https://doi.org/10.5194/egusphere-egu23-15745, 2023.

Ecohydrologically suitable microsites, such as surface depressions and micro-topographical barriers acting as sink patches intercepting and infiltrating runoff, as well as nurse shrubs have largely been proposed as tools to improve the establishment of tree vegetation in Mediterranean reclaimed landscapes and other degraded dryland environments. We analyze the impact of sink patches and nurse (Genista scorpius) shrubs developed in Mediterranean-dry reclaimed mining hillslopes (Utrillas field site, central Spain) on seedling performance up to 8 years after plantation of two tree species with contrasted water-use strategies: Pinus nigra, a drought avoider species, and Quercus ilex, a drought tolerant species. Nurse shrubs enhanced early establishment of seedlings in shaded spots under its canopy. Further, sink patches ameliorated the survival of both species, although only increased plant growth during wet years that promoted source-to-sink transference of surface water resources as surface runoff. The survival and growth of P. nigra seedlings were strongly constrained during dry periods, resulting in a high cumulative mortality after 8 years regardless of microsite. Q. ilex showed a better performance during the experiment, keeping the positive effects of suitable microsites on plant survival after 8 years of plantation. Overall, our results encourage the use of ecohydrologically suitable microsites that concentrate water resources and nurse shrubs that ameliorate local conditions as key spots for introducing late-successional tree species in Mediterranean-dry reclaimed mining sites. Our results also indicate that seedling functional strategy to cope with drought is a critical factor conditioning plantation performance, therefore constituting a fundamental species selection criterion for restoration actions in Mediterranean areas, especially under effects of climate change.

How to cite: Vicente, E., Moreno de las Heras, M., Merino-Martín, L., Nicolau, J. M., and Espigares, T.: Sink patches, nurse shrubs and plant water-use strategies control the establishment of tree seedlings in Mediterranean-dry reclaimed mining hillslopes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16963, https://doi.org/10.5194/egusphere-egu23-16963, 2023.

Soil degradation of the spoil ground generated during the construction of expressways is a serious concern, and the ecological environment of the mound created by the unplanned piling of abandoned soil is poor. Revegetation could quickly and efficiently restore the ecological environment of the spoil ground. This study aimed to explore the direct and indirect effects of different fertilization treatments on the remediation of spoil ground soil using vetiver grass, and determine the most appropriate combination of fertilizers to help repair the ecological environment of the spoil ground. To study the changes in the physicochemical properties, enzyme activity, microorganisms in rhizosphere soil, and plant characteristics of vetiver grass, 12 treatments were set up, including no fertilization (CK), a single application of nitrogen fertilizer (N1:150 kg/ha, N2:300 kg/ha, and N3:450 kg/ha), a single application of phosphorus fertilizer (P1:350 kg/ha and P2:700 kg/ha), and a chemical fertilizer combination (NP: N1P1, N2P1, N3P1, N1P2, N2P2, N3P2). Compared with CK, combined nitrogen and phosphorus fertilization improved the physicochemical properties, enzyme activities, microbial diversity of rhizosphere soil and the plant traits, more significantly than the treatment with nitrogen or phosphorus fertilization alone. Path analysis showed significant differences between the direct and indirect paths of plant characteristics under the N, P, and NP treatments. NP treatment was more helpful in improving the soil environment of spoil ground, because NP treatment had a higher path coefficient for plant traits (NP (0.807) > N (0.703) > P (-0.993)) and enzyme activities (NP (0.897) > P (0.767) > N (0.373)). N2P2 had the highest comprehensive score (34), indicating that N2P2 could be used as an effective fertilizer combination.  These results indicate that the benefits of appropriate cultivation and fertilization practices to help restore degraded soil. Combined fertilization treatment (NP) improved the path coefficient of soil physicochemical properties to plant traits and soil enzyme activities, and thus better restored the habitats of spoil ground.

How to cite: Bai, L. and Shi, P.: Rapid restoration of spoil ground along expressways through a combination of vetiver grass cultivation and fertilization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1823, https://doi.org/10.5194/egusphere-egu23-1823, 2023.

 In order to comprehensively consider the impact of human activities on runoff simulation and improve the accuracy of runoff simulation, so as to make a more accurate prediction of the future runoff of the Hanjiang River Basin, this study improved the reservoir module of the Wespa model, adding two parts: reservoir inflow data correction and water storage and outflow data calculation without measured data. Use the improved model to verify its applicability to the Hanjiang River Basin, then, choose the ones who has the most familiar trend with the historical data in the future climate model data (CMIP6). Put the selected data in the model to predict the runoff of Hanjiang River from 2021 to 2060. By analyzing the future runoff trend of Ankang, Huangjiagang and Huangzhuang in the Hanjiang River Basin from 2021 to 2060 and the changes of average runoff, seasonal runoff and monthly runoff compared with the historical period (1981-2020), the conclusions drawn are as follows: (1) The improved Wetspa model has good applicability in the Hanjiang River Basin; (2) The future runoff of Ankang section is decreasing, while that of Huangjiagang and Huangzhuang sections is increasing; (3) Compared with the reference period, the average runoff of the three sections in the future shows an increasing trend, which indicates that there will be flood risk in the future; (4) Compared with the reference period, the runoff proportion of the three sections will increase in spring and winter, and decrease in autumn. Attention should be paid to the risk of drought in autumn. In terms of months, the proportion of runoff from April to June increases, decreases from September to November, and increases and decreases in other months are uncertain.

How to cite: Zhou, X., Chen, W., Liu, Q., Shen, H., Cai, S., and Lei, X.: Future runoff forecast in Hanjiang River Basin based on Wetspa model and  CMIP6 model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2215, https://doi.org/10.5194/egusphere-egu23-2215, 2023.

The hydrological conditions are key factors in ensuring the health of water ecosystems. The lack of runoff data constrains the assessment of the basin's evolutionary pattern of the eco-hydrological conditions. The Yongding River Basin (YDRB) is a typical water-scarce basin in northern China, where the changing environment has led to widespread water scarcity and ecosystem degradation problems. In response to the shortage of information at the upper reaches of the YDRB at the Xiangshuibao gauging station, this study adopted a distributed hydrological model, WetSpa, to simulate the daily runoff data in this station from 1960 to 2019. Then, Indicators of Hydrologic Alteration (IHA) was used to identify the most ecologically relevant hydrological indicators (ERHIs) and further determine the "true" eco-hydrological variation point in the basin. Finally, the evolution rule of the eco-hydrological conditions in the basin was analyzed and the overall hydrological alteration degree of the Xiangshuibao Section was determined. The results showed that the rising rate, decline rate, annual maximum 1-day flow, annual minimum 1-day flow, annual maximum flow occurrence time, and July flow were the ERHIs. The variation period was from 1980 to 1986. Except for the annual maximum 1-day flow and decline rate were moderate variation indicators, all others were low variation indicators. The overall hydrological variability of the Xiangshuibao section was low. The results of this study were intended to provide a reference for ecological management construction in the YDRB and other similar areas.

How to cite: Yang, Y. and Cai, S.: Analysis of the hydrological conditions based on hydrological model in a data-scarce basin: A case study in the Yongding River Basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3101, https://doi.org/10.5194/egusphere-egu23-3101, 2023.

The project of the Yangtze-to-Huaihe River diversion focuses on urban and rural water supply, taking into both irrigation and water supply as well as improving the ecology of Chaohu Lake. It is a major strategic water resource allocation project across river basins and across provinces. This study used a combination of a simulation model and optimization technology to establish an annual water dispatch model based on the principle of water balance for the Yangtze-to-Huaihe River diversion project and employs genetic algorithms to optimize the proportion of the two-line river diversion for the section of Yangtze River-to-Chao lake. The possible scenarios of the annual water dispatching model were analyzed from two aspects of runoff water condition and water use planning, and typical years scheduling scenarios were established, including short-term planning and long-term planning of low flow years, short-term planning and long-term planning of normal flow years, and short-term planning and long-term planning of high flow years. The annual water dispatch model was used to simulate the annual scheduling schemes for these different scenarios, and the results of water diversion and water supply, divisional scheduling, and lake storage conditions were compared and analyzed for scheduling schemes. The simulation results showed that the water shortage in the near-term planning level year (2030) and the long-term planning level year (2040) was basically zero in the flat water year and the abundant water year, and there was a large water shortage in the dry water year in both the near-term and long-term planning level years, mainly in agriculture. The total amount of water diversions for each typical year in the scheduling scheme was thus significantly reduced compared with that in the design plan. In the far and near future planning, the abandoned water was less in the dry water year and relatively more in the rich water year and the flat water year, and the abandoned water was similar in the two lakes in the flat water year, while the abandoned water mainly occurs in Chaohu Lake in the rich water year. The northern section of the river was the main object of the water supply of the river-supply project, and the supply of this section accounts for about 57% of the total amount in the dry water year, more than 75% of the total amount in the flat water year, and more than 97% of the total amount in the rich water year. From the viewpoint of the whole section of the project, the water supply in the dry water year was the largest, the lake utilization in the flat water year was the largest, and the abandonment rate in the abundant water year is the largest under the near and long term planning. The results of this study can provide a certain foundation and reference value for the construction of project scheduling operation and scheduling system.

How to cite: Zhang, L., Lei, X., Wang, C., Ji, Y., and Sun, J.: Research on the Annual Water Dispatch Model of the Yangtze-to-Huaihe River, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4031, https://doi.org/10.5194/egusphere-egu23-4031, 2023.

In fragile karst watershed, landscape pattern mainly affects evapotranspiration, interception, surface runoff, soil water infiltration and groundwater formation through spatiotemporal variation of land use, vegetation pattern, and then influences the discharge and sediment transport. A new Vegetation-Topographic factor (VTF)was constructed by NDVI and DEM data from 2000 to 2018. Based on VTF classification , Vegetation-Topographic landscape index(VTLI) was calculated by FRAGSTATS to analyze the impact of VTLI change on runoff and sediment yield in Nandong underground river system（NURS）. The results showed that :(1) PD, IJI, LSI, SHDI were significantly positively correlated with runoff and sediment, while AI, CONNECT were significantly negatively correlated with runoff and sediment yield(P<0.05). LPI and DIVISION indices were not significantly correlated with discharge, but positively correlated with sediment yield. (2) PD, IJI, LSI and SHDI were the main promoting factors for runoff, while LSI and SHDI were the main promoting factors for sediment yield. CONNECT and AI were the main restrain factors of sediment yield, Which showed a downward trend. (3) In urban areas, VTF was decreased and has persistence trend. In basin-mountain margin areas, VTF was increased and has persistence trend. In mountain area, VTF was unchanged or not significantly increased but was anti-persistence trend. The change of landscape pattern indexes varied the runoff and sediment yield of NURS. The trend and persistence of VTF vary greatly in different geomorphic positions of NURS. These results will provide theoretical basis for watershed management and soil conservation of karst fragile ecosystem in southwest China. 

How to cite: Liu, P., Li, Y., and Yu, Y.: Landscape pattern change affect runoff and sediment yield in Nandong underground river system, Southwest China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4222, https://doi.org/10.5194/egusphere-egu23-4222, 2023.

Groundwater-dependent ecosystems (GDEs) exist all over the world, especially in water-limited regions. To achieve better water management, it is necessary to map and identify GDEs. Central Asia (CA) is one of the most arid regions in the mid-latitudes and one of the major regions with shallow groundwater tables. However, the role of groundwater in the impacts of climate change and regional anthropogenic activities on environmental risks, especially regional desertification, is inadequately understood due to the limited available research on GDEs. In the present study, a remote sensing-based method was used for mapping GDEs in regional CA, and three means—overlay analysis, correlation analysis, and the water balance method—were adopted to validate the accuracy of the mapping outcomes. Our results indicated that: 1) GDEs were concentrated around large lakes and in central Kazakhstan (between 46°N and 50°N latitudes), and areas "Very Likely" and "Likely" to be GDEs accounted for 36.89%, and 28.85% of the total natural vegetation areas, respectively; 2) at the watershed scale, the Sarysu Basin had the largest proportion (94.02% of the area) of potential GDEs while the Ysyk-Kol Basin had the lowest proportion (17.84%); 3) all the three validation methods indicated a good performance for our GDE mapping results. We concluded that the remote sensing-based GDE identification method can be considered a potential approach for mapping GDEs regionally. Better recognition of relationships among groundwater availability, ecosystem health and groundwater management policies should be developed by conducting further studies, to protect GDEs and to prevent regional land degradation.

How to cite: Liu, H., Liu, C., Zhao, W., Yu, Y., and Yetemen, O.: Mapping Groundwater-dependent Ecosystems in Arid Central Asia: Implications for Controlling Regional Land Degradation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5218, https://doi.org/10.5194/egusphere-egu23-5218, 2023.

Vegetation distribution are of great significance to control soil erosion and water and soil loss on slope.  In order to further explore the influence of slope vegetation distribution on the process of sediment yield and discharge, and quantitatively analyze the relationship between vegetation distribution and sediment yield and discharge. Through field rainfall simulation, under the condition of 15° slope, the sediment yield and runoff were observed under the conditions of different vegetation coverage (40%, 60%), different rainfall intensity (30, 60, 90 mm/h) and different vegetation distribution positions (relative distance 0, 0.2, 0.4, 0.6, 0.8, 1). The results showed that: (1) under a certain slope and rainfall intensity, the runoff yield and sediment yield increased rapidly at first and then tended to be stable under different vegetation distribution conditions. (2) In this study, the average runoff yield and sediment yield firstly decreased and then increased with the increase of the relative distance. The average runoff yield of the slope with the relative distance of 0.2 was the minimum. (3) The random forest algorithm shows that rainfall intensity and vegetation coverage have important effects on runoff yield, and rainfall intensity and vegetation relative distance have important effects on sediment yield. (4) When the vegetation coverage was 40%, the optimal vegetation relative positions were 0~0.36 and 0~0.31, respectively, with the main objective of reducing runoff and sediment. When the vegetation coverage was 60%, the optimal relative vegetation positions were 0~0.43 and 0~0.22, respectively, to reduce runoff and sediment. This study shows that slope vegetation distribution has an important effect on sediment yield and runoff. Under the same vegetation coverage, the smaller the relative distance of the grass belt, the better the effect of reducing runoff and sediment. The research results can provide theoretical basis and data support for optimal allocation of vegetation in the process of ecological restoration.

How to cite: Sun, R., Ma, L., Zhang, J., and Hu, Y.: Evaluation of the effects of grassland distribution on erosion processes of the loess hillslopes under simulated rainfall, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16505, https://doi.org/10.5194/egusphere-egu23-16505, 2023.