Research on the optimal allocation of agricultural water and soil resources in the Heihe River Basin based on SWAT and intelligent optimization

In arid areas, vegetation is the basis for maintaining the virtuous cycle of ecosystems, while water resources are the key factor restricting the survival of vegetation communities. The balance between water resources and vegetation is related to the sustainable development of ecological benefits and economic benefits in arid areas. Although research on the carrying potential of vegetation in arid areas has been emphasized, there is still a lack of spatial analysis of different vegetation types over large areas. Therefore, this study takes precipitation as the basic source of water resources, calculates the amount of available water resources in the basin from the available effective precipitation and available irrigation water, and it analyzes the spatial distribution of forest and grass vegetation types under the water resources constraint, combined with the ecological water demand of different vegetation types and based on the principle of “Water to determine the Vegetation”. The results showed that the ecological water demand of each vegetation type was as follows: Forest > Shrub Vegetation > Grassland Vegetation > Desert Vegetation. The range of comprehensive available water resources of vegetation was from 0 to 221.71 mm, which decreased with the altitude gradient. Then, the spatial distribution pattern of vegetation types constrained by the water resources in the Aksu River Basin showed a striped distribution from north to south, with shrub vegetation in the high-altitude mountainous area, grassland vegetation in the low-altitude area, and desert vegetation in the desert plain area, respectively, accounting for 29.05%, 10.74%, and 53.45% of the total basin. This research approach provides a scientific basis for the planning of forest and grass vegetation construction in arid regions.

Section: Study Areamentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Optimization of Forest and Grass Vegetation Distribution in the Aksu River Basin by Water Resources Carrying Capacity

Qi,

Xi,

Cui

et al. 2024

“…The TOPMODEL model is mainly used for terrain-based simulations, and it is incapable of reflecting the spatial changes of hydrological information. Many scholars have analyzed the adaptability of SWAT models in various conditions [31][32][33][34] and evaluated the impact of land use change and climate on runoff using this model [35][36][37][38][39]. In spite of these achievements, there are indeed limitations for different basins.…”

Section: Introductionmentioning

confidence: 99%

Simulation and Evaluation of Runoff in Tributary of Weihe River Basin in Western China

Liu,

Su,

Wang

et al. 2024

Model simulation plays a significant role in the water resources cycle, and the simulation accuracy of models is the key to predicting regional water resources. In this research, the Qianhe tributary at the Weihe River basin in Western China was selected as the study area. The tributary was divided into 29 sub-basins and 308 hydrological response units according to the spatial raster data and attribute data of the hydrology, meteorology, topography, land use, and soil types. On this basis, a soil and water assessment tool (SWAT) model for runoff simulation and evaluation of this region was established. A sensitivity test and parameter calibration were then executed on 15 parameters involved with surface runoff, soil flow, and shallow underground runoff. The simulation results demonstrate a calibration and verification error of 3.06–10.08%, with very small uncertainties throughout the simulation, whereas they exhibit relatively large errors in the simulation of the dry period (winter) but, in contrast, quite small errors in the rainy period (summer). In addition, the simulated runoff with a low value is overestimated. When the annual, monthly, and daily runoff are 4–13.5 m3/s, 4–69.8 m3/s, and 40–189.3 m3/s, respectively, the relative error is smaller, and the simulation results are more accurate. The sensitive parameters predominantly affecting the runoff simulation of the basin include soil evaporation compensation, runoff curve coefficient, vegetation transpiration compensation, and saturated hydraulic conductivity in this region. In the case of hypothetical land use change scenarios, we observe a great reduction in simulated runoff in arable land, woodland, and grassland, while we observe an increment in construction and residential land and wasteland. The annual and monthly runoff are increased by above 54.5%. With the increase in cultivated land and forestland, the annual and monthly runoff decrease by 24.6% and 6.8%, respectively. In the case of hypothetical scenarios under 24 climate combinations, if the precipitation remains unchanged, the increase and decrease in temperature by 1 °C leads to a decline and increment of runoff by −0.72% and 5.91%, respectively. With regard to the simulation for the future under the RCP2.6 and RCP8.5 climate scenarios, downscaling was employed to predict the runoff trend of the future. In short, this study provides a method for runoff inversion and water resources prediction in small mountainous watersheds lacking hydrological and meteorological observation stations.

“…Based on the groundwater model, the relationship between base flow and recharge in mountainous areas in the upper reaches of the Heihe River [8], groundwater equilibrium and water cycle evolution under water resource management scenarios such as the history and future of agricultural irrigation and water conservation in the middle reaches of Zhangye Basin [9,10], and the eco-hydrological effect of Ejina Banner under environmental flow management of the Heihe River downstream were studied [11]. Based on the SWAT model and intelligent optimization, the optimal allocation of agricultural water and soil resources in the middle reaches of the HRB and Zhangye areas was studied [12]. The coupling model of soil water and groundwater was used to study the water cycle process in Zhangye area under historical and future water-saving scenarios [13], and the soil water balance model and numerical model of farmland gas wrapping zone based on empirical assumptions were used to study the soil water balance in Zhangye agricultural irrigation area [14].…”

Section: Introductionmentioning

confidence: 99%

Coupling Simulation and Prediction of Sustainable Utilization of Water Resources in an Arid Inland River Basin under Climate Change

Qi,

Li,

Zheng

et al. 2023

The arid endorheic basin of northwest China is characterized by rich land resources, water shortage, and a fragile ecological environment. The establishment of a credible coupling model of groundwater and surface water based on multi-source observation data is an effective means to study the change in basin water cycles and the sustainable utilization of water resources in the past and future. Based on the latest understanding of hydrogeological conditions, hydrology and water resource utilization data in the middle reaches of the Heihe River Basin (HRB), this paper constructs an up-to-date coupling model of surface water and groundwater to study the water balance change of the basin. The water resources data series under historical replay and CMIP5 climate model prediction are constructed to predict future changes in water resources. The study shows that, under the joint influence of natural conditions and human activities, the average annual recharge of groundwater in the study area from 1990 to 2020 is 17.98 × 108 m3/a, the average annual discharge is 18.62 × 108 m3/a, and the difference between recharge and discharge is −0.64 × 108 m3/a. The total groundwater storage is −19.99 × 108 m3, of which the groundwater storage from 1990 to 2001 was −17.52 × 108 m3 and from 2002 to 2020 was −2.47 × 108 m3. Abundant water from 2002 to 2020 in the basin significantly improved the loss of groundwater storage. Under the prediction of historical reappearance and the CMIP5 CNRM-CM5 model RCP4.5 and RCP8.5 pathways, the groundwater level of the Heihe River–Liyuanhe River inclined plain falls first because the HRB has just experienced a wet season and then rises according to future climate change. The groundwater level of the inclined plain east of the Heihe River and Yanchi basin decreases continuously because of the change in water cycle caused by human activities. The erosion accumulation plain is located in the groundwater discharge zone, and the water level is basically stable. Under the conditions of water resource development and utilization, the runoff of Zhengyixia hydrological station cannot meet the requirements of the “97 Water Dividing Plan” of the State Council in most years in the future, and the ecological and production water in the lower reaches of HRB cannot be effectively guaranteed. With the implementation of water-saving irrigation under the RCP4.5 and RCP8.5 scenarios, the runoff of Zhengyixia can meet the “97 Water Diversion Plan”. It is suggested to further improve the level of agricultural water savings in the middle reaches of the HRB and control the reasonable scale of cultivated land in order to reduce water consumption in the middle reaches of the HRB and implement sustainable utilization of water resources in the HRB.