Date Site Was Built Upon

Author:  Steve Custer, Earth Sciences, Montana State University, Bozeman, MT 59717-3480
Data Compiled by:  Steve Custer, Andrea Wright, Stewart Dixon, Robert Snyder,  Daryl Chipman, and Luke Lohmuller
(Last Modified by Steve Custer 17 October 1999; 02 January 2010)

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Example Questions the Database Can Answer

1.  When was the site built (all years)?
 

The Following Themes are available.

  1. Map 1:  Year built
  2. Map 2:  When was site built displayed in 10 year increments
        1850-1899
        1900-1909
        1910-1919
        1920-1929
        1930-1939
        1940-1949
        1950-1959
        1960-1969
        1970-1979
        1980-1989
        1990-1997

This data can be seen as an animation as well.

Map 1 Date Built

This map shows when a site was built.  There is some ambiguity regarding date built.  The date can come from Geocode, from the date the septic permit was issued or the date that the well was drilled.  The date built under geocode is used if all three dates are present. If Geocode is absent and well and septic both have dates, the oldest of those two dates is used.  If Geocode is absent and only well or septic has a date, that date is used.  The younger dates for septic system permit may be due to modifications of the septic system or to a delay between permit issuance  and inspection.  A younger date for a well might indicate a redrilled site or a septic system permit that was awarded with a well being drilled later.
 

Map 2 Year Built

This graphic shows several themes which depict the where sites were built in 10 year increments.  This is a static view of the  animation.

Glossary

Geocode:  The Montana Department or Revenue (DOR) assigns a unique code to all taxable property called a Geocode.  This code indicates the county, township, range, and section as well as quarter quarter quarter section and unit number.  The Geocode is correct to section, but quarter sections and units have different strategies for assignment of code depending on operator and are not dependable as locators.

Septic Permit:  Each septic system installed since 1966 must have a septic system permit.  The permit numbers are assigned sequentially and are recorded in the county courthouse.

Well Number:  The Ground-Water Information Center has received copies of all well logs for wells drilled since ????.  Each well is assigned a well identification number or M-number.  This number allows one to find well data in the GWIC database.

About the Data


This map shows the date of construction indicated by DOR, Well  Log or Septic Permit.    The data comes from three sources:
 1.  The CAMAS data base maintained by the Montana Department of Revenue (DOR) The DOR data base includes information on property address, date built and utilities present.  Utilities include well, septic system, public and community water, public and community septic systems, and Gas.  DOR sites are identified with a unique Geocode. If the geocode location could be identified based on address or subdivision lot and block the point was digitized from the 1995 Gallatin County Road Book by coordinating section corners with the Gallatin County Public Land Survey System (PLSS) data  and associated relevant permit data was attached.  If the point cannot be located the point is not digitized.  Each Geocode has a date built associated with it.
 2.  Well location data available from the Montana Ground-Water Information Center.  Again, if a well could be located based on address or subdivision, block and lot, the point was entered and data regarding the M-number or GWIC identification number was added as was date drilled.  The point  was digitized from the 1995 Gallatin County Road Book by coordinating section corners with the Gallatin County Public Land Survey System (PLSS) data  and associated relevant permit data was attached. Each well has a date completed attached to the M-number.
 3.  Septic system location data available from the Gallatin County Department of Environmental Health (GCDEH).
The GCDEH data is in the septic permit file.  If the septic permit location could be identified based on address or subdivision lot and block the point was digitized on the 1995 Gallatin County Road Book by coordinating section corners with the Gallatin County Public Land Survey System (PLSS) data  and associated relevant permit data was attached.  Each permit number has a date issued and a date inspected.  Date issued is used for this database.
 

If more than  septic permit or well identification number (M-number) exists for an address, this number is simply recorded as a multiple number for that point and no new point is “spawned”.  As a result the duplicate points do not have unique locations.  The well-septic database assumes only one location for each address in the road book.  Multiples are recorded but not given unique point locations.  Information about whether there is a well or septic system present is recorded, but detailed information about well properties or septic properties are not provided.  Detailed attribute data regarding wells can be found in the well coverage.  Not all points show either a well or a septic system.  Each structure indicated on the road book was recorded regardless of whether there is well or septic system information present.  In summary, the presence or absence of a well and/or septic system is recorded and duplicates or multiples at a site are ignored.

Summary of the four files welsep, welfnl, sepfnl, geocshp, and their differences.  (There are two primary differences between the welsep and the coverages  named geocshp, welsep and septicfnl.  First, the welsep file contains information drawn from three sources Department of Revenue Geocode database (well and septic data); the Montana Bureau of Mines and Geology Ground Water Information System (wells); the Gallatin County Septic Permit database (septic system).  These data are drawn together so that data from multiple sources can be assessed at the same time.)  If multiple wells, geocodes, or septic systems are listed at a site, only one point is given, but there are multiple columns for other septic system, well number, or geocode unit number at that point.

Alternatively, there are three separate geocode, well, and septic data bases (geocshp, welfnl, and septicfnl,) these databases have had the locations where multiple geocodes wells or septic systems are indicated at a single site moved arbitrarily located several m from the first point so that each has a unique point location.  This information also allows one to explore the data base from different sources and the data from that source without dealing with the information from the other sources. (Although the geocode (parcel ID without the county number and the A97) is reported on all three data bases so that there is a common code.

Definition of attributes from the welsep attribute table is attached.