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Layer: BMAP Credit Areas (ID: 12)

Name: BMAP Credit Areas

Display Field: BMAPID

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description: To produce the baseload layers that will allow estimating baseloads (and subsequently load reductions) from small BMPs, such as swales, relatively small input grid cells must be utilized in the basin layer that is one of the inputs to the custom SWIL 4.0 model run. Previous efforts determined the polygon grid cell size to be acceptable at 2500 square meters. A grid layer of 50-meter by 50-meter cells was created to cover the entire spatial extent. This resulted in over 1 million grid cells to cover the entire watershed. It is important to note that partial grid cells along the extent boundary with an area of less than 500 square meters were removed from the grid layer prior to model execution due to limitations of the SWIL model. For those partial grid cells, values were calculated post-model execution utilizing the normalized loads of the closest adjacent grid cell to assign an accurate load.In order to efficiently run the model with this large of a basin (grid) count, mean rainfall and ET rasters were created for years 2004-2017. This allowed the model to be executed as a single year. Aggregated rainfall rasters were created by averaging the identical months for each year for the POR (2004-2017). For the evapotranspiration rasters, the MOD 16 data product is only available for the years of 2000-2014. To account for this lapse in data from 2015 to 2017, monthly mean rasters were created for the POR in which the measured ET data was available (i.e. the average of identical months for every year from 2000 to 2014). The mean POR ET rasters were then used for years 2015-2017. Once the model outputs were generated by the execution of the model, the period -of-record mean annual and dry season (January - May) tabular values were joined to the spatial grid cell layer. The outputs of each grid cell was then normalized by using the area of each grid cell. The normalized results included in this layer are representative of annual and dry season (January through May) sums for direct runoff, baseflow and total (direct runoff + baseflow) values of three parameters (volume, total nitrogen (TN), and total phosphorus (TP)) per grid cell. A verification model run was performed in order to validate the results of the basin load layer. The verification model run consisted of using the complete monthly (2004-2017) temporal extent for the rainfall and ET rasters for three relatively small areas and comparing the outputs to the basin load layer. The results of the verification analysis demonstrated no significant difference whether average rasters were used or all the monthly rasters for the entire POR were used.

Service Item Id: 92d613816f7d42c09c740de408a65c34

Copyright Text: This data set was compiled by Applied Ecology, Inc.

Default Visibility: false

MaxRecordCount: 2000

MaxSelectionCount: 2000

Supported Query Formats: JSON, geoJSON, PBF

Min Scale: 500000.0

Max Scale: 0.0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: true

Can Modify Layer: true

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:
Drawing Info: Feature Draw Order: Advanced Query Capabilities:
HasZ: true

HasM: true

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:
Supported Operations:   Query   Query Attachments   Query Analytic   Generate Renderer   Return Updates

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