GLEAMS was developed to evaluate the impact of management practices on potential pesticide and nutrient leaching within, through, and below the root zone. It also estimates surface runoff and sediment losses from the field. GLEAMS was not developed as an absolute predictor of pollutant loading. It is a tool for comparative analysis of complex pesticide chemistry, soil properties, and climate. GLEAMS can be used to assess the effect of farm level management decisions on water quality.
GLEAMS is a continuous simulation, field scale model, which was developed as an extension of the Chemicals, Runoff and Erosion from Agricultural Management Systems (CREAMS) model. GLEAMS assumes that a field has homogeneous land use, soils, and precipitation.
It consists of four major components: hydrology , erosion/sediment yield, pesticide transport, and nutrients. GLEAMS can provide estimates of the impact management systems, such as planting dates, cropping systems, irrigation scheduling, and tillage operations, have on the potential for chemical movement. Application rates, methods, and timing can be altered to account for these systems and to reduce the possibility of root zone leaching.
The model also accounts for varying soils and weather in determining leaching potential. GLEAMS can also be useful in long-term simulations for pesticide screening of soil/management. The model tracks movement of pesticides with percolated water, runoff, and sediment. Upward movement of pesticides and plant uptake are simulated with evaporation and transpiration. Degradation into metabolites is also simulated for compounds that have potentially toxic products.
Erosion in overland flow areas is estimated using a modified Universal Soil Loss Equation. Erosion in chemicals and deposition in temporary impoundments such as tile outlet terraces are used to determine sediment yield at the edge of the field.
|Latest Version||3.0 (2000)|
|State of Development||Released and final|
|Current Development Activity||None. Last minor bug fix was 2007.|
|Management Domains||Land, Freshwater|
|Subdomains||Contaminant Losses, Erosion/Sediment|
|Intended End Users||
|Temporal Extents||Years, Decades|
|Steady State or Dynamic||Dynamic|
|Level of Integration||Environmental|
|Key Input Data||Land Use|
|Input Data Formats||ASCI|
|Output Data Formats|
|Open/Closed Source||Open Source|
|Operating Systems||MS Windows|
|User Interface||Graphical desktop|
|Ease of Use||Please Select|
|Use in Policy Process||Plan (Policy Formulation), Review (Issue Identification)|
GLEAMS home page with Source code and documenation available, as well as links to publications. - http://www.tifton.uga.edu/sewrl/Gleams/gleams_y2k_update.htm
|Methods included for calibration and validation||None|
|Keywords||leaching, nutrient, pesticide, root zone, soil erosion, sediment yield, hydrology|
GLEAMS Homepage - http://www.tifton.uga.edu/sewrl/Gleams/gleams_y2k_update.htm
GLEAMS - Publications and Abstracts
This study of predicted impacts of proposed earthworks focuses upon a 201-hectare parcel of land that lies to the south of the Whenuapai airbase.
Numerous applications worldwide but mostly in USA