A Generic Approach for Live Prediction of the Risk of Agricultural Field Runoff and Delivery to Watercourses: Linking Parsimonious Soil-Water-Connectivity Models With Live Weather Data Apis in Decision Tools

Alexis Comber,Adrian L Collins,Yusheng Zhang,Andrew Smith,Andrew Turner,David Haro-Monteagudo,Tim Hess

doi:10.3389/fsufs.2019.00042

Alexis Comber, Adrian L Collins + Show 5 more

Open Access

https://doi.org/10.3389/fsufs.2019.00042

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Abstract

This paper describes the development and application of a novel and generic framework for parsimonious soil-water interaction models to predict the risk of agro-chemical runoff. The underpinning models represent two scales to predict runoff risk in fields and the delivery of mobilized pesticides to river channel networks. Parsimonious field and landscape scale runoff risk models were constructed using a number of pre-computed parameters in combination with live rainfall data. The precomputed parameters included spatially-distributed historical rainfall data to determine long term average soil water content and the sensitivity of land use and soil type combinations to runoff. These were combined with real-time live rainfall data, freely available through open data portals and APIs, to determine runoff risk using SCS Curve Numbers. The rainfall data was stored to provide antecedent, current and future rainfall inputs. For the landscape scale model, the delivery risk of mobilized pesticides to the river network included intrinsic landscape factors. The application of the framework is illustrated for two case studies at field and catchment scales, covering acid herbicide at field scale and metaldehyde at landscape scale. Web tools were developed and the outputs provide spatially and temporally explicit predictions of runoff and pesticide delivery risk at 1 km2 resolution. The model parsimony reflects the driving nature of rainfall and soil saturation for runoff risk and the critical influence of both surface and drain flow connectivity for the risk of mobilized pesticide being delivered to watercourses. The novelty of this research lies in the coupling of live spatially-distributed weather data with precomputed runoff and delivery risk parameters for crop and soil types and historical rainfall trends. The generic nature of the framework supports the ability to model the runoff and field-to-channel delivery risk associated with any in-field agricultural application assuming application rate data are available.

Highlights

Rainfall-induced surface and subsurface runoff mobilizes and transports the chemicals used for in-field agricultural applications from land to receiving freshwaters
This research is informed by two limitations arising from previous work: the difficulties of determining antecedent soil water status and the temporally static nature of many landscape scale decision support tools in this domain
It is applicable to small catchments (≤ 6,500 ha) (NRCS, 2002) and has been implemented in models to estimate agrochemical transport to water (e.g., SWAT—Arnold et al, 1998; PRZM— Carsel et al, 2003; APEX—Williams et al, 2006; CREAMS— Knisel, 1980) and has been shown to be robust for a range of climates, soil types and land uses (e.g., Gassman et al, 2007)

Summary

Introduction

Rainfall-induced surface and subsurface runoff mobilizes and transports the chemicals used for in-field agricultural applications (fertilizers, herbicides, and pesticides) from land to receiving freshwaters. The SCS Curve Number (CN) method (USDA SCS, 1972) is commonly used to model surface runoff depth from rainfall amount, soil surface characteristics and antecedent wetness. It is applicable to small catchments (≤ 6,500 ha) (NRCS, 2002) and has been implemented in models to estimate agrochemical transport to water (e.g., SWAT—Arnold et al, 1998; PRZM— Carsel et al, 2003; APEX—Williams et al, 2006; CREAMS— Knisel, 1980) and has been shown to be robust for a range of climates, soil types and land uses (e.g., Gassman et al, 2007). Many CN models predict runoff depths for individual weather events using an empirical relationship between direct runoff depth, rainfall amount, soil surface characteristics and antecedent wetness (USDA, 2004). The antecedent soil water status has been estimated from 5day antecedent rainfall (e.g., Mishra et al, 2005), this has been shown to be poorly correlated with maximum potential retention (USDA, 2004)

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