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Citation_Information:
Originator:
Groundwater Inventory and Mapping Project, a cooperative effort between the Water Bureau - Michigan Department of Environmental Quality, USGS - Michigan Water Science Center and Michigan State University - Institute of Water Research, RS&GIS and Biosystems and Agricultural Engineering. This project was mandated by P.A. 148 (Michigan Acts of 2003). Major funding was provided by MDEQ, supplemented with additional funds from the USGS Cooperative Water Program. Publication_Date: October 28th, 2005
Title: Glacial Deposits - Estimated Yield
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Publication_Information:
Online_Linkage: <http://gwmap.rsgis.msu.edu/>
Online_Linkage: <http://www.mcgi.state.mi.us/mgdl/>
Larger_Work_Citation:
Citation_Information:
Originator: Groundwater Inventory and Mapping Project
Publication_Date: August 18th,2005
Title:
Executive Summary - Public Act 148: Groundwater Inventory and Map Project Edition: 1st
Geospatial_Data_Presentation_Form: Adobe PDF document
Online_Linkage: <http://gwmap.rsgis.msu.edu/>
Description:
Abstract:
The data points used to create this raster grid were obtained from Wellogic, the Michigan Department of Environmental Quality Statewide Groundwater Database (SGWD). Wellogic contains approximately 425,000 water well records found within the State of Michigan, and although it represents the best available data, it cannot be considered a complete database of all the wells or well records in existence. The well files were downloaded by county and merged together to create a statewide file. In the merge process any well that fell outside of its designated county boundary was removed from the original data set. Approximately 270,000 records were used in this file after the inconsistent point locations and bad data values were removed. A series of additional attributes were added to the database, this is a brief overview of how the well locations were processed:
A GIS data update utility created at MSU was used to process and merge the county wells; this also added many glacial drift and rock well fields, and percentages for aquifer drift material based on the existing Wellogic and lithology database information. Next the percentages of aquifer material and trend information were calculated for the drift index. These fields were used by the USGS to further calculate the wells estimated yield values. A detailed account of these processes can be found later on in this document. Purpose:
Yield from a local area in the commonly-used portion of the glacial deposits was mapped as the estimated pumping rate (gallons per minute) that would cause a fifty-percent decrease in the water level in the pumping well (sometimes referred to as available drawdown). This fifty-percent threshold value accounts for the generally accepted manner that high-capacity water wells operate (i.e. well efficiency). The estimated yield was calculated using a simple analytical equation to combine transmissivity, the saturated thickness and a storativity value of 0.0016, which is typical of a leaky-confined aquifer.
The yield map should not be viewed as a guarantee of yield from a well at a specific location. Supplemental_Information:
Areas of thin glacial deposits (<30 feet thick) are shown because legally-constructed water wells screened in the glacial deposits of these areas are unlikely. The no-data areas on the map are zones more than 2000 meters away from a well record in Wellogic. This 2000-meter buffer zone balances the desire to note areas that lack data in Wellogic with the need for a statewide estimate. To flag these areas in this raster grid, negative values were assigned. Thin glacial deposits (<30 feet thick) were assigned a "-1" value. No-data areas were assigned a "-2" value.
It should also be noted that all islands were removed from the State because inadequate amounts of well locations were present to estimate a grid surface. Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: October 28, 2005
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -90.488871
East_Bounding_Coordinate: -82.122124
North_Bounding_Coordinate: 47.500217
South_Bounding_Coordinate: 41.632056
Keywords:
Theme:
Theme_Keyword: Wells
Theme_Keyword: Wellogic
Theme_Keyword: Estimated Yield
Theme_Keyword: Transmissivity
Theme_Keyword: Groundwater
Theme_Keyword: Grid surface
Place:
Place_Keyword: Michigan
Place_Keyword: State
Access_Constraints: No restrictions on access
Use_Constraints: No restrictions on use
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Justin M Booth
Contact_Organization:
Remote Sensing and GIS Research and Outreach Services, Michigan State University Contact_Position: Information Technology Professional
Contact_Address:
Address_Type: mailing and physical address
Address: Geography Building, Michgan State University
City: East Lansing
State_or_Province: MI
Postal_Code: 48824
Contact_Voice_Telephone: (517)432-0446
Contact_Facsimile_Telephone: (517)353-1821
Data_Set_Credit:
Remote Sensing & GIS Research and Outreach Services - Department of Geography; Institute of Water Research; Biosystems and Agricultural Engineering, US Geological Survey, Michigan Water Science Center Native_Data_Set_Environment:
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722 |