## 4 Discussions
### Implications to Wetland Remediation and Reclamation, Limitation, and Future Research  
The areas of wetlands cover more than 50% of the landscape in the Athabasca Oil Sands Region (AOSR). The wetlands in this region have been changed significantly due to the extensive development of the oil sands and the associated human activities. These disturbed changes can result in ecohydrological feedbacks that can affect the subsurface flow, water table, soil moisture, NEE, biodiversity, and peat decomposition. Wetland creation, restoration, and enhancement are commonly used to offset lost wetland functions. Despite the ubiquity of perturbations in the AOSR, knowledge of their cumulative impacts on wetland hydrologic functioning remains incomplete. Only a few studies have addressed the potential long-term changes to the groundwater table, which is a balance of charge and discharge in watersheds in the AOSR [33]. As a result, a better understanding of spatiotemporal variability with coupled groundwater dynamics in the region is an important first step before properly characterizing the impacts of perturbations, such as the construction of open mines, well pads, and industrial and living facilities on the recharge-discharge function of wetlands and the updated mitigation policy in the AOSR [33; 63; 64].  
The modified SWAT model can simulate recharge-discharge water dynamics and their effects on the biogeochemical cycling, such as CO\({}_{2}\) and NEE, particularly in the wetlands. Because we kept all the functions of hydrological processes in the original SWAT, themodified SWAT model can analyze not only wetlands lost or degradation at the site scale, but also wetland variability at the regional scale due to the land-use change of wetland regions resulting from the human disturbance in past and present regional profiles. These past and present profiles of the wetland landscape can be used to make decisions regarding the type and location of restorations. This implies that a cumulative impact in reclamation and remediation could be estimated quantitatively to identify the key hydrologic variables, chemical variables, and charge-discharge in the wetland region over time and improve restoration practice.  
However, the modified SWAT model has limitations. First, the HRU in the SWAT limits the resolution of the different types of wetlands, although this spatial resolution could be improved if small HRUs are used. In an HRU, all the wetlands are considered a percentage of the landscape, but wetland shape and boundary would not be resolved. Therefore, the modified SWAT remains to be developed in distinguishing different types of wetlands, such as bog, fen, marsh, and disturbed wetlands in the future. Soil parameters are spatially volume-averaged. This means that only one type of wetland can be represented in an HRU. Second, the validation results are slightly poor compared to calibration in Table 3. This is because the weather conditions have not been captured fully. In the cold region, it is still challenging to simulate the freeze-thaw cycle and permafrost process. CO\({}_{2}\) and CH\({}_{4}\) emissions are sensitive to the freeze-thaw cycle and permafrost processes [20]. This implies that the wetlands in the cold region are vulnerable to climate change. Finally, a restorative practice using different reclamation techniques requires development to represent wetland construction and restore disturbed areas. Varying levels of anthropogenic disturbance and different reclamation techniques should also be represented to account for both the reclamation practices and specific wetlands in the AOSR [65; 66].