WEPP模型坡面版在黄土丘陵沟壑区的适用性评价——以坡度因子为例

利用安塞试验站1985-1992年的气象观测数据和野外坡度径流小区径流和土壤侵蚀量监测资料,评价了WEPP模型在黄土丘陵沟壑区不同坡度条件下的适用性。结果表明,径流量的模拟值在10°、15°、20°、25°和28°五个坡度条件下,变化幅度不如实测值明显,但模拟值随坡度变化的趋势和实测值相一致;WEPP模型对次降雨、年平均和多年平均土壤侵蚀量模拟结果较好,且无论是模拟值在不同坡度之间的差值、还是模拟值随坡度变化趋势均与实测值接近。I30对WEPP模型模拟次降雨径流量有重要影响,当I30大于0.92mm/min,模型模拟误差较大。WEPP模型对次降雨土壤侵蚀量的模拟与PI30密切相关,当PI30大于129mm2/min时,模型模拟误差较大。∑PI30对WEPP模型模拟年平均径流量和侵蚀量有重要影响,当∑PI30大于150mm2/min时,模拟精度明显下降,且∑PI30对径流模拟影响较对土壤侵蚀模拟影响明显。WEPP模型对次降雨、年平均和多年平均径流量模拟的Nash-Sutcliffe有效性ME分别为0.914、0.912和0.617;对次降雨、年平均和多年平均土壤侵蚀量模拟的Nash-Sutcliffe有效性ME...

川中丘陵区坡耕地侵蚀空间分布的WEPP模型和^137Cs法研究

IEECAS SKLLQG

WEPP在黄土高原坡面径流调控中的适用性研究

针对黄土高原坡面降雨径流调控优化难以采用数学模型的情况,根据杨凌岭后降雨径流调控试验站部分降雨、产流、产沙观测资料,对WEPP 2006年坡面版应用于黄土高原坡面产流、产沙模拟计算的适用性进行了研究。结果表明:WEPP可对降雨径流调控措施下的径流量和产沙量进行模拟计算,但需对模型参数进行率定,并根据实测资料进行验证;WEPP对缓坡径流量和产沙量的模拟计算优于对陡坡的模拟计算,对裸地径流量和产沙量的模拟计算优于对径流调控措施(苜蓿地)的模拟计算,对径流量的模拟计算优于对产沙量的模拟计算。

WEPP模型的最新研究进展

WEPP(Water Soil Loss Equation)作为新一代水蚀预报模型,是指导水土保持措施优化配置、水土资源保护与持续利用的有效工具。近年来,遥感和GIS技术为WEPP快速获取所需资料、处理数据、图像编辑和输出等提供可靠的技术支撑;同时,区域化、尺度概念的引入,为WEPP应用于大尺度提供技术保障。为借鉴WEPP模型的优点,促进我国水蚀预报模型的发展,对WEPP模型的最新发展进行了详尽的介绍,并对WEPP应用到我国时可能存在的问题进行了初步分析。

Avaliação dos modelos de predição da erosão hídrica MEUPS e WEPP: contribuição em bacias hidrográficas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

USLE and WEPP Soil Erosion Models: Their Applicability and Use in Generating Cover Values to Stabilize Soil in the Los Alamos, New Mexico Area

Soil erosion is a naturally occurring process that involves the detachment, transport, and deposition of soil particles. Disturbances such as thinning and wildfire can reduce cover greatly and increase erosion rates. Forest managers may use erosion prediction tools, such as the Universal Soil Loss Equation (USLE) and Water Erosion Prediction Project (WEPP) to estimate erosion rates and develop techniques to manage erosion. However, it is important to understand the differences and the applications of each model. Erosion rates were generated by each model and the model most applicable to the study site, Los Alamos, New Mexico was determined. It was also used to find the amount of cover needed to stabilize soil. The USLE is a simpler model and less complicated than a computer model like WEPP, and thus easier to manipulate to estimate cover values. Predicted cover values were compared to field cover values. Cover is necessary to establish effective erosion control guidelines.

Water erosion prediction project (WEPP) forest applications /

"August 1997."

MODELAJE DE LA EROSIÓN DE SUELOS EN COSTA RICA MEDIANTE EL MODELO WEPP

El objetivo de esta investigación consiste básicamente en probar la aplicabilidad para las condiciones físico-geográficas características de Costa Rica, del modelo para la predicción de suelos Watcr Erosion Prediction Project (WEPP), el cual es desarrollado por el Servicio de Conservación de Suelos de los Estados Unidos.Los pronósticos efectuados por el WEPP, son comparados con mediciones reales de erosión y escorrentía efectuadas por medio de parcelas tipo USLE (café, pastos y tabaco-maíz-frijol) ubicadas en la localidad de Cerbatana de Puriscal (1990-1995), junto con mediciones de las condiciones climáticas y análisis de las características de los suelos.Los resultados indican que ci modelo tiene un aceptable pronóstico en los datos de la erosión y de la escorrentía, sobre todo si se le compara con pronósticos hechos con la Ecuación Universal de Pérdida de Suelos. Los parámetros de entrada (input) que requiere el WEPP son muy abundantes en cantidad y muy sensibles en su efecto sobre los pronósticos, por lo tanto el uso y la interpretación de los resultados deben efectuarse con un enfoque muy crítico.Abstract: the objective of this invcstigation basically consists of testing the suitabiiity of the model Water Erosion Prediction Project (WEPP) to predict soil erosion given the physical geographical charactcristics of Costa Rica. The model was developed by the Soil Conservation Service of the United States.Thc effectted predictions of the WEPP are compared with real soil erosion and surface runoff measurements taken at a typical USLE site (coffee, pasture and tobacco-corn-bean), located in the surroundings of Cerbatana of Puriscal (1990-1995). This data was taken in conjuntion with measurements of ciimactic conditions and analysis of soil characteristics.The results indicate that the model has an acceptable ability to predict soil erosion and surface runoff data, particularly if one compares thern with predictions made with the Universal Soil Loss Equation. Thc input variables that are rcquired by WEPP are quite abundant in quantity and are very sensitive in their effect of the predictions made. For that reason, the uses and interpretation of the results should be put into use with a very critical eye.

Runoff, sediment loss and water quality from forest roads in a southeast Queensland coastal plain Pinus plantation

Runoff and sediment loss from forest roads were monitored for a two-year period in a Pinus plantation in southeast Queensland. Two classes of road were investigated: a gravelled road, which is used as a primary daily haulage route for the logging area, and an ungravelled road, which provides the main access route for individual logging compartments and is intensively used as a haulage route only during the harvest of these areas (approximately every 30 years). Both roads were subjected to routine traffic loads and maintenance during the study. Surface runoff in response to natural rainfall was measured and samples taken for the determination of sediment and nutrient (total nitrogen, total phosphorus, dissolved organic carbon and total iron) loads from each road. Results revealed that the mean runoff coefficient (runoff depth/rainfall depth) was consistently higher from the gravelled road plot with 0.57, as compared to the ungravelled road with 0.38. Total sediment loss over the two-year period was greatest from the gravelled road plot at 5.7 t km−1 compared to the ungravelled road plot with 3.9 t km−1. Suspended solids contributed 86% of the total sediment loss from the gravelled road, and 72% from the ungravelled road over the two years. Nitrogen loads from the two roads were both relatively constant throughout the study, and averaged 5.2 and 2.9 kg km−1 from the gravelled and ungravelled road, respectively. Mean annual phosphorus loads were 0.6 kg km−1 from the gravelled road and 0.2 kg km−1 from the ungravelled road. Organic carbon and total iron loads increased in the second year of the study, which was a much wetter year, and are thought to reflect the breakdown of organic matter in roadside drains and increased sediment generation, respectively. When road and drain maintenance (grading) was performed runoff and sediment loss were increased from both road types. Additionally, the breakdown of the gravel road base due to high traffic intensity during wet conditions resulted in the formation of deep (10 cm) ruts which increased erosion. The Water Erosion Prediction Project (WEPP):Road model was used to compare predicted to observed runoff and sediment loss from the two road classes investigated. For individual rainfall events, WEPP:Road predicted output showed strong agreement with observed values of runoff and sediment loss. WEPP:Road predictions for annual sediment loss from the entire forestry road network in the study area also showed reasonable agreement with the extrapolated observed values.

CLIGEN非降水要素在黄土塬区的适用性评估

许多基于物理机制的水文和作物模型需要日序列气象数据来驱动,CLIGEN是为WEPP等模型产生气候输入文件的天气发生器,可以产生10个日序列气象变量来满足这种需要,但是其在中国的适用性需要进行评估。研究的目标是利用黄土高原陕西长武1957~2001年的气象数据评估CLIGEN产生非降水要素(最高温度、最低温度、露点温度、太阳辐射和风速)的能力。结果表明,CLIGEN对最高温度、最低温度和露点温度的模拟效果较好,对太阳辐射和极端气候事件的模拟效果较差,对风速的模拟效果最差。相关性检验表明CLIGEN很好地保持了气象要素的季节性,这对模拟农业生产是非常重要的;但是没有保留气象要素逐日的自相关和互相关性,进而导致产生的温度变化不符合连续渐变的规律。

解集GCM输出模拟黄土塬区土壤水分平衡的潜在变化

壤水分平衡对气候变化存在着响应,在全球变化的大背景下,研究土壤水分的可能变化是气候变化影响评估中非常重要的一项内容。目标是利用经验统计方法解集GCM网格逐月的降水和温度数据,并使用建立的气候变化情景作为WEPP的输入文件评估黄土高原王东沟流域2010～2039年土壤水分平衡(土壤水分、蒸发、渗漏和蒸腾)的可能变化。结果表明,3种情景预测2010～2039年王东沟流域年均降水可能增长1.8%～17.5%,年最高温度和最低温度分别可能增长0.5～0.9℃和2.0～2.3℃。作物蒸腾变化主要在4～6月份,土壤蒸发变化主要发生在7～9月份;作物蒸腾年均变化-5%～19%,土壤水分年均变化-4%～4%,土壤蒸发年均变化-7%～7%,均为A2a减少,B2a和GGal增大;A2a的土壤水分渗漏增长最大,GGal次之,B2a基本不变。这些结果表明气候变化及其导致的作物生长变化对土壤水分平衡存在重要的影响。

细沟股流剥蚀率与载沙量以及沟长的耦合关系

土壤剥蚀是指由侵蚀动力引起的土壤颗粒从土壤母质移动的过程。细沟剥蚀土粒随着细沟股流中含沙量的增加而减少 ,已有的一些侵蚀模型 (如 WEPP)均提到了这一点。用黄土高原一种典型的粉壤土 ,在 5种坡度、3种流量下进行了细沟侵蚀模拟试验。对试验结果进行了回归 ,分析了黄土高原斜坡及陡坡地、细沟股流剥蚀率随含沙量以及沟长变化的函数关系。这对细沟侵蚀动力过程的研究深入 ,以及对侵蚀过程的预测预报提供了有力的参考依据

土壤侵蚀预报模型研究进展

介绍了国内外土壤侵蚀预报模型的主要研究成果。所介绍的国外土壤侵蚀预报模型除众所周知的USL E/ RUSL E,WEPP,L ISEM和 EUROSEM外 ,还有浅沟侵蚀预报模型 (EGEM)和切沟侵蚀预报模型。国内的侵蚀预报模型主要有在 GIS支持下的陡坡地包括浅沟侵蚀的坡面侵蚀预报模型、有一定物理成因的坡面侵蚀预报模型和流域预报模型。在总结和评价国内外土壤侵蚀预报模型的基础上 ,提出了中国今后土壤侵蚀预报模型研究的设想。

陡坡细沟含沙水流剥蚀率的试验研究及其计算方法

细沟剥蚀土粒随着细沟股流中含沙量的增加而减少 ,这一概念已在一些侵蚀模型 (如 WEPP)中得到应用。用黄土高原一种典型的粉壤土 ,在 5种坡度 (5°,10°,15°,2 0°,2 5°) ,3种流量 (2 ,4,8L/m in)条件下进行了细沟侵蚀模拟试验 ,试验沟长 0 .5～ 8m。通过 40 5次试验 ,确定了不同坡度、入流量条件下 ,侵蚀产沙量与细沟长度的定量函数关系。在假定细沟径流和土壤侵蚀沿细沟的行为相同条件下 ,提出了一种计算含沙水剥蚀率的方法 ,并进一步表达了细沟剥蚀率随含沙量以及沟长变化的函数关系。实验结果在 15°,2 0°,2 5°时表现出很好的显著性

Rotina computacional e equação simplificada para modelar o transporte de sedimentos num Latossolo Vermelho Distrófico

Os objetivos do presente trabalho foram desenvolver rotina computacional para a solução da equação de Yalin e do diagrama de Shields e avaliar uma equação simplificada para modelar a capacidade de transporte de sedimento num Latossolo Vermelho Distrófico que possa ser utilizada no Water Erosion Prediction Project - WEPP, assim como em outros modelos de predição da erosão do solo. A capacidade de transporte de sedimento para o fluxo superficial foi representada como função-potência da tensão cisalhante, a qual revelou ser aproximação da equação de Yalin. Essa equação simplificada pôde ser aplicada em resultados experimentais oriundos de topografia complexa. A equação simplificada demonstrou acuracidade em relação à equação de Yalin, quando calibrada utilizando-se da tensão média cisalhante. Testes de validação com dados independentes demonstraram que a equação simplificada foi eficiente para estimar a capacidade de transporte de sedimento.