An enhanced rainfall–runoff model with coupled canopy interception

Abstract

The translation of rainfall to runoff is significantly affected by canopy interception.Therefore, a realistic representation of the role played by vegetation cover when modelling the rainfall-runoff system is essential for predicting water, sediment, and nutrient transport on hillslopes. Here, we developed a new mathematical model to describe the dynamics of interception, infiltration, and overland flow on canopy-covered sloping land.Based on the relationship between rainfall intensity and the maximum interception rate, the interception process was modelled under two simplified scenarios (i.e., r e ≤ Int m and r e > Int m ). Parameterization of the model was based on consideration of both vegetation condition and soil properties. By analysing the given examples, we found that Int m reflects the capacity of the canopy to store the precipitation, k reveals the ability of the canopy to retain the intercepted water, and the processes of infiltration and runoff generation are impacted dramatically by Int m and k. To evaluate the model, simulated rainfall experiments were conducted in 2 years (2016 and 2017) across six cultivation plots at Changwu State Key Agro-Ecological Experimental Station of the Chinese Loess Plateau.The parameters were obtained by fitting the unit discharge (simulated rainfall experiments in 2016) using the least squares method, and estimation formulas for parameters pertaining to vegetation/soil factors (measured in 2016) were constructed via multiple nonlinear regressions. By matching the simulated results and unit discharge (simulated rainfall experiments in 2017), the validity of the model was verified, and a reasonable precision (average R 2 = .86 and average root mean square error = 6.45) was obtained.The model developed in this research creatively incorporates the canopy interception process to complement the modelling of rainfall infiltration and runoff generation during vegetation growth and offers an improved hydrological basis to analyse matter transport during rainfall events. K E Y W O R D S overland flow, physical-based model, rainfall interception, vegetation growth

Knowledge Production for Resilient Landscapes: Experiences from Multi-Stakeholder Dialogues on Water, Food, Forests, and Landscapes

“…Transpiration and evapotranspiration [44] Canopy interception [45,46] Hydraulic redistribution, moving water from moist to dry soil through plant roots [47,48] Plants play a part in hydrological cycles by controlling water runoff [49] Release of volatile organic compounds contributing to: Intensification of rainfall and an overall cooling effect by blocking incoming solar energy [50]; Secondary organic aerosol condensing atmospheric moisture [51]. Trees recharge atmospheric moisture [34] and influence cloud formation [52] Vegetation helps to regulate climate by cycling vast amounts of water and maintaining the gaseous composition of the atmosphere [53] Terrestrial moisture recycling [54,55] Precipitation recycling [34,56] The biotic pump theory-precipitation in continental interiors from atmospheric circulation driven and maintained by large, continuous areas of forest starting from the coastline [57,58] Arial rivers-cross-continental transport of atmospheric moisture affecting downwind water availability [34]…”

Effect of digital elevation model spatial resolution on depression storage

“…Some rainfall is intercepted and retained by the vegetation cover, and the remainder reaches the ground and infiltrates at a rate dependent on soil conditions. When the rainfall intensity exceeds the soil infiltration rate, surface depressions are filled, and the water stored in these depressions is denoted as DS (Tiwari, 2021;Tao et al, 2020). Surface runoff is initiated when Xinyi Li and Jingming Hou should be considered joint first author.…”