| Groundwater and surface water resources are the important part of water cycle, and also can maintain social and economic development and guarantee the regional ecological security. Under the condition of the shortage of water resources in our country, how to get the more water resources and high water utilization efficiency under the premise that not destroy the ecological environment is the key measure to solve the contradiction between the current serious shortage of water resources and the increasing water resources demands.Sanjiang Plain(10.9×104km2) in northeast China is one of China’s largest grain production bases and China’s largest inland freshwater wetland region, and have plays an important role in ensuring food security in China and in the regional ecological security. Under the background of continuously decreased groundwater level and formed cone of depression and leading to degeneration of wetland that caused by the over exploited groundwater and using less surface water, this article presented the joint control of groundwater and surface water under the condition of ecological security, and establishing the coupled simulation model of groundwater and surface water by means of fully understanding evolution characteristics of water cycle parts and the interaction between the groundwater and surface water. Moreover, analyzing the various schemes for the development of water resources, determining reasonable combination control scheme of groundwater and surface water, providing technology support to efficient utilization of water resources and regional ecological security.This article showed the following results1.The evolution characteristics of water cycle factors of the Sanjiang PlainAnalyzed the evolution characteristics of temperature, rainfall, surface runoff and groundwater level by using mathematical statistics methods,Annual temperature showed a rising at a rate of 0.26℃/10 a of the Sanjiang Plain;the annual precipitation showed a slightly changing, but the rainy period and the dry period showed decreased and increased trends, respectively. Annual precipitation showed a slowly rising at a rate of 6 mm /10 a of the Sanjiang Plain; from 1956-2012,the runoff of the main rivers showed a significantly downward trend in the annual. In addition, the total surface water resources was 15.34 billion cubic meters and the usable water resources was 4.71 billion cubic meters.Groundwater level in the study area continues to decline, and showed a decline at a rate of 0.3m/a, and the groundwater table of near river region,irrigation region and far river region decreased in the velocity of 0.27m/a,0.80m/a and 0.56m/a, respectively.2. The interaction between of groundwater and surface water in the Sanjiang PlainBased on hydrochemical similarity principle, we researched the regional-scale interaction of surface water and groundwater by using Hierarchical Cluster Analysis(HCA) and Principal component analysis(PCA) methods combined with the statistical methods on the Sanjiang Plain(10.9×104 km2) in northeast China in order to gain insights into sustainable shallow groundwater usage in this intensively irrigated agricultural region. 102 water sampling(60 from shallow groundwater, 7deep groundwater and 35 surface water) were collected and grouped into three clusters and seven sub-clusters during the analyses. The PCA analysis identified four principal components of the interaction, which explained 85.9% variance of total database.The study showed that rivers in the upper part of the region received the recharge from the local shallow groundwater; While for the middle part, there is relatively active connection between the shallow groundwater and surface water. As for the lower part, the shallow groundwater largely received the recharge from the surface water.3. Water resources availability quantity calculation of the Sanjiang PlainThe study showed that the total surface water resource was 15.34 billion cubic meters, and the allowable using surface resources quantity was 4.71 billion cubic meters under fully consideration of the ecology water requirement of rivers base flow, water for delivery sediment capacity and aquatic ecological water requirement. In addition, we got the exploited groundwater quantity was 4.654 billion cubic meters by using the water balance and exploitation coefficient method. In this paper, the results showed that most of groundwater resources that can be mined mainly distributed in the plains region, and the second is the low hilly land region,next is Xingkai lake plain and the last is a mountainous area.4. Seting up coupled simulation model of groundwater and surface water of the Sanjiang PlainEstablished the conceptual model and mathematical model of groundwater and surface water based on the geological conditions,hydrogeological conditions, land use type and the surface hydraulic parameters. Then established the coupled simulation model of groundwater and surface water of the Sanjiang Plain by using the FOEC(First-order exchange coefficient) method and got the parameter identification and verification. The results was good and can generally represented the actual conditions of water resources of the Sanjiang Plain.5. Simulating the evolution of groundwater under different water schemes(1). Getting the range of suitable groundwater level in the Sanjiang PlainGetting the lower suitable groundwater level by using the empirical formula based on the 102 groundwater depth data from 2008 to 2012;Gaining the upper suitable groundwater level by using capillary rise height of 18 different soil types through standpipe method and rooting depth of typical surface vegetation of the Sanjiang Plain. Getting the suitable groundwater level in the Sanjiang Plain through field sampling and laboratory experiments: the upper suitable groundwater level from0.5 m to 2.8 m and the lower suitable groundwater level ranged from2.0 m to 14.3 m.(2).Water resources exploition based on the groundwater quantity and groundwater table double controlSimulating the four different water schemes by using the established coupled model of groundwater and surface water, and finally got the results under the control of ecological ideal shallow groundwater level and groundwater quantity. the results showed that : if mining the water resources according to the current situation, the groundwater level will continue to fall and the aquifer reserves will decline. And the groundwater level of wet year, normal year and dry year would less than the lower of ecological ideal shallow groundwater level at 2028, 2023 and2019, respectively. For scheme 2, the allowable withdrawal shallow groundwater and surface water availability serve as for irrigation,groundwater and surface water resources of wet year, normal year and dry year can support rice paddies under water saving irrigation which covers an area of 3.30 million hectare(1.97 million hectare of conventional irrigation), 3.19 million hectare(1.90 million hectare of conventional irrigation), 3.11 million hectare(1.85 million hectare of conventional irrigation), respectively; For scheme 3, in order to support4.0 million hectare rice paddies, we should exploit the groundwater and surface water under the wet year 6.50 billion cubic meters,8.61 billion cubic meters( where water from international water 3.90 billion cubic meters), respectively. In the same time, we should exploit the groundwater and surface water under the normal year 5.85 billion cubic meters,9.27 billion cubic meters(where water from international water4.55 billion cubic meters), respectively. we should exploit the groundwater and surface water under the dry year 5.04 billion cubic meters,10.01 billion cubic meters(where water from international water5.36 billion cubic meters), respectively. |
PDF Full Text Request