# Research on the Jiamusi Area's Shallow Groundwater Recharge Using Remote Sensing and the SWAT Model
## 4 Results
### Calculation of Groundwater Recharge in the Jianusi Area by the SWAT Model
#### 4.2.3 Calculation of Groundwater Resources Based on SWAT  
The model's simulation of the water reserves in the phreatic layer at the end of each year resulted in averages that were correlated with the sub-basins, as previously regionalized (refer to Figure 9). Overall, the groundwater reserves in the basin were distributed quite differently. Among these, Jianusi City, the hub, showed the primary tendency of the No. 1 watershed, with the southeast direction rapidly falling. The primary cause is that agricultural planting occupies 75% of the area in the northeast and southeast, and a significant amount of irrigation water was required. Furthermore, the river's main stem lies in the far southeast of the region; therefore, the available water supply is minimal. The primary trend of the No. 2 basin was declining from Fuyuan City in a southwesterly direction. This is primarily due to Fuyuan's location in the basin's entire exit, near Heilongjiang's main river, which has a sizable lateral supply. The No. 1 basin's southwest region is adjacent to Tongjiang City, and both have comparable groundwater storage capacities. Furthermore, the simulation findings' net groundwater discharge trend was essentially in line with the real circumstances. As it moved from the center outward, drainage basin No. 1 gathers water in the southeast and northwest directions. The sub-drainage basins 1, 2, 3, and 5 of the Songhua River had very little water reserves in the phreatic layer, and the water resources were primarily surface water. Sub-basins No. 8 and No. 9 are situated in agricultural planting areas with significant groundwater withdrawals and are impacted by groundwater storage. Basin No. 2 diminishes from northeast to southwest. Figure 8: Determination and verification of the runoff model (the above two pictures are the simulation results of Tongjiang Hydrology Station, and the next two pictures are the simulation results of Fuyuan Hydrology Station. The ordinate indicates the amount of runoff. Unit: m\({}^{3}\), the horizontal coordinate is the year). Using groundwater balancing, groundwater storage characteristics in the Jiamusi area of the No. 1 and No. 2 watersheds were computed and summarized from 2010 to 2016 (two years of preheating) (see Table 10). It was evident that the Jiamusi area is over-exploited and that the average storage variable is \(-\)357 million m\({}^{3}\)/a. The biggest simulated runoff, with a storage variable of 1.416 billion m\({}^{3}\)/a, occurred in 2016. Positive equilibrium exists. Eighty-six percent of the groundwater in the drainage system comes from base flow recharged rivers. The lowest is the form loss of regression bag, which accounts for only 3.50%, and the second is approximately 13.85%, mostly because of the refilling of deep aquifers. Plant roots' absorption of water from shallow water levels is the primary cause of water loss. The Jiamusi region has a wide yearly temperature variation and a temperate continental climate. Evapotranspiration and rainfall differ too much from one another. The Songhua River basin's potential emission increase is expected to rise in the twenty-first century. The area is mostly renewed by atmospheric precipitation, although there are a number of surface-level variables that contribute to the inadequate replenishment. The principal causes are the extended duration of the winter season, the frozen river, and the substantial groundwater supply to the river. Because of the intricate geology of the Jiamusi area and the disparate hydrogeological conditions of each molecular basin, the evaluation of water resources was based on the division of molecular basins and the characteristic hydrological year. Monthly measured runoff data from 2009 to 2018 were chosen from the Tongjiang Hydrology Station, which is the entire downstream of the No. 1 basin. The general dry year 2011 (\(p\) = 75%) was synthesized using the empirical frequency analysis approach, with an annual discharge of 662 million m\({}^{3}\).