Dynamic Crop Coefficients in SWAT Model for Green Water Evaluation
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Solution Overview
Problem
Current water resources evaluation methods inadequately simulate green water resources, leading to errors in identifying effective green water, which is crucial for sustainable management and utilization.
Innovation Solution
A method using dynamic crop coefficients within the SWAT model to evaluate effective green water resources by accounting for vegetation type characteristics, growth stages, and changing coverage, incorporating meteorological and soil data to accurately simulate evapotranspiration and leaf area index changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Penman-Monteith formula is used to calculate reference evapotranspiration, then the applicability and ability to simulate vegetation growth process is improved, but the accuracy of actual evapotranspiration for different vegetation types deteriorates because crop-specific characteristics are not considered
Solution Approach 1:
The patent introduces dynamic crop coefficients (Kc) that change according to vegetation type, growth stage, and environmental conditions. These coefficients modify the reference evapotranspiration calculated by Penman-Monteith formula to obtain actual evapotranspiration, thereby adapting the general formula to specific crop requirements while maintaining its broad applicability
Solution Approach 2:
The patent employs dynamic rather than static crop coefficients that vary with vegetation growth stages (initial, mid-season, late season), environmental conditions, and vegetation characteristics. This dynamic approach allows the model to accurately reflect the changing actual evapotranspiration throughout the vegetation growth period
2Ease of manufacture
If static coverage coefficient is used to calculate effective green water, then the calculation simplicity is improved, but the accuracy deteriorates because vegetation coverage is constantly changing with growth
Solution Approach 1:
The patent replaces static coverage coefficients with dynamic crop coefficients that change according to vegetation growth stages and environmental conditions. This dynamic approach accurately reflects the changing vegetation coverage and its impact on effective green water throughout the growth period
Solution Approach 2:
The patent establishes predetermined relationships between crop coefficients and vegetation growth stages, allowing the model to automatically determine appropriate coefficients based on the current growth stage without requiring real-time manual adjustment of coverage values
3Adaptability or versatility
If green water resources are incorporated into water resources evaluation, then the comprehensiveness and reasonableness of evaluation system is improved, but the complexity of evaluation increases due to need to distinguish effective and ineffective green water
Solution Approach 1:
The patent segments green water resources into effective green water (directly used by crops for production) and ineffective green water (soil evaporation from bare land, sandy land, etc.). This segmentation allows the evaluation system to comprehensively assess all green water while clearly identifying the portion that directly supports agricultural production
Solution Approach 2:
The patent applies different evaluation criteria and coefficients to different land use types and vegetation categories. Effective green water from crops uses dynamic crop coefficients, while ineffective green water from bare land or non-agricultural areas uses different coefficients, allowing tailored evaluation for each local condition
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of green water simulation and crop growth process, enabling more precise evaluation of effective green water resources and guiding better water resource management.
Implementation Method 1
Green water is the water consumed by forests, grasslands, wetlands and farmland through evapotranspiration
Implementation Method 2
Penman-Monteith formula with strong applicability is generally used to calculate evapotranspiration in the evaluation of green water resources
Implementation Method 3
the SWAT model to simulate vegetation coverage every day according to the judgment result
Data Source
AI summary
The present disclosure relates to a method of evaluating effective green water resources based on dynamic crop coefficients and a device thereof. The method includes constructing a SWAT model of an area to be measured; constructing a mathematical relation expression of vegetation potential transpiration, and introducing dynamic crop coefficients into the SWAT model; evaluating results obtained by operating the SWAT model according to the measured evaporation data and leaf area index monitoring data obtained in advance, and calibrating crop growth parameters and evapotranspiration parameters; judging evaporation effectiveness according to a land cover type and a dynamic coverage calculation method, and carrying out daily simulation to obtain a total amount of effective green water resources in the area to be measured.