Evaluation of the performance and complexity of water quality models for peatlands

Abstract

Rewetting is accepted as an effective technique in restoring degraded peatlands. However, it may adversely impact water quality, particularly in nutrient-rich peatlands. The aim of this study was to review water quality models applied to peatlands, with a focus on evaluating the performance (such as stability and accuracy) and complexity of the models. In a systematic review of published studies from 01/01/2003 to 10/12/2023, out of 3618 published studies on peatlands and nutrient modelling, only 23 studies applied water quality models to predict the evolution and distribution of nutrients of peatlands by using 16 different water quality models. Out of the 23 studies, only 1 predicted the nutrient concentration and transport of a rewetted peatland. Among the 16 models evaluated, only the mixed mire water and heat (MMHW) model was capable of considering the inherent heterogeneity in peatland characteristics. The HYDRUS 1D/2D model is effective at predicting nitrogen species, despite encountering challenges in some studies due to the complex nature of the peat environment. To enhance the predictive power of water quality models, it is important to consider all the processes that can affect the concentration of nutrients in peatlands such as oxidation of carbon, the nitrogen cycle, decay/production rate for nutrients, adsorption/desorption of nutrients in the soil, and the advection of nutrients due to the influence of ground water and surface water. To date, no peatland-specific water quality model has been developed to simultaneously predict DOC, nitrogen and phosphorus in peatland ecosystems.