Layer:Well Logs

Source:NSE, Sustainability and Applied Science Division and NSDEM, Geoscience and Mines Branch

Nova Scotia Well Logs Database

The Nova Scotia Well Logs Database is maintained by Nova Scotia Environment. The most recent version of the Nova Scotia Well Logs Database (Microsoft® Access 2000 format) is available for download at: http://www.gov.ns.ca/nse/groundwater/welldatabase.asp

The following provides a description of the some of the key fields shown in the interactive well logs map layer. Additional description of fields is provided in the Nova Scotia Well Logs Database user manual available at: http://www.novascotia.ca/nse/groundwater/docs/Well.Logs.Database.Manual.pdf

The Nova Scotia Department of Natural Resources enhanced georeferenced version of the Well Logs Database can be downloaded in a GIS format: http://www.novascotia.ca/natr/meb/download/dp430.asp.

Note that the value -9999 in the data table denotes a null value.

Abbreviations:

DEPTH = Well depth, metres
CASING = Length of casing, metres
BEDROCK = Depth to bedrock, metres
STATIC = depth to static water level, metres
YIELD = Preliminary short-term driller yield estimate, litres per minute
ELEVATION = Well elevation based on digital elevation model, metres above sea level
DRILLER = Well driller registration number
TYPE = Well type, dug or drilled

Notes About Georeferencing Fields

UTM Coordinates (Northings and Eastings)
Northings and eastings are in NAD83, zone 20 metric units.

UTM coordinates in the database have been approximated based on the various levels of available georeferencing accuracy. The method used is recorded in the Georef M field, the source of the data is recorded in the Georef S field, and the associated accuracy of the UTM is recorded in the Georef A field.

Georef M
This field indicates the georeferencing method used to assign UTMs to the well logs. The following ten codes are used in the database:

G = GPS
Well UTMs estimated using GPS or survey equipment. Note that the UTM coordinates of wells constructed after 2004 have been recorded by well contractors using handheld GPS units (well drillers only). These UTMs were taken directly from the coordinates reported on the original well logs from 2004-2006, whereas the well logs entered after 2006 were subject to QA/QC. Well locations have also been identified based on available reporting (e.g. System Assessment Reports, etc.).

M = Map
Well UTMs estimated from map or site plan showing approximate well location.

D1 = Centroid of Property using Nova Scotia Property Registration Database (NSPRD)
Where a Property Identification (PID) number could be associated with a well log, the centroid of the property was used to assign a UTM to the well log.

D2 = Property Location using Nova Scotia Property Registration Database (NSPRD)
The UTMs were estimated by recording latitude and longitude coordinates of the assumed building location for a given PID using Property Online (NSPRD) and converting to northing and eastings. In some cases the UTMs were estimated from a GPS measurement at the site.

A1= Nova Scotia Mapbook Centroid
The centroid of the grid reference assigned to the well log was used to generate a UTM for the well log.

A2 = Nova Scotia Atlas Centroid
The centroid of the grid reference assigned to the well log was used to generate a UTM for the well log.

B1 = NTS Claim Centroid
The centroid of the grid reference assigned to the well log was used to generate a UTM for the well log.

B2= NTS Tract Centroid
The centroid of the grid reference assigned to the well log was used to generate a UTM for the well log.

C = Community Centroid from Nova Scotia Gazeteer file
The Nova Scotia Gazeteer was used to locate the well log based on the community location on a map.

Georef S
This field indicates the source of the georeferencing. In some cases the UTM was recorded at the wellhead and is indicated as ‘Well UTM’, whereas in other cases a UTM of the property or another on-site well was recorded. These UTMs are indicated as ‘Site UTM’. Some of the common sources of georeferencing include the following:
-Nova Scotia Mapbook (Mapbook)
-Nova Scotia Atlas (Atlas)
-NTS Grid System (NTS-Tract,Claim)
-Well UTM - Well Log (UTM recorded by driller)
-Nova Scotia Property Registration Database (NSPRD)
-System Assessment Report
-Nova Scotia Gazeteer File
-CBWRDB (Historical Mapping contained in the Cape Breton Water Resource Database)

Georef A
This field provides an approximation of the accuracy of the UTMs. The following is a general guide of the methods used to estimate the georeference accuracy:

G = GPS
Where PDOP or UTM accuracy information was recorded, these values are used to indicate georeference accuracy. In most cases this information was not recorded, however, and it was assumed that the georeference accuracy using GPS is on the order of ±15 m.

M = Map
Well UTMs estimated from map or site plan showing approximate well locations. The estimated georeference accuracy generally ranges from 50 to 100 m.

D1 = Centroid of Property using Nova Scotia Property Registration Database (NSPRD)
To provide a general indication of the accuracy of the UTM estimate, the square root of the property PID area recorded in the NSPRD is shown as the estimated georeference accuracy.

D2 = Property Location using Nova Scotia Property Registration Database (NSPRD)
To provide a general indication of the accuracy of the UTM estimate, the square root of the property PID area recorded in the NSPRD is shown as the estimated georeference accuracy.

A1 = Nova Scotia Mapbook Centroid
The minimum georeference accuracy is estimated as ½ of the hypotenuse of the 1000 m x 1000 m grid square (±707 m).

A2 = Nova Scotia Atlas Centroid
The minimum georeference accuracy is estimated as ½ of the hypotenuse of the 938 m x 875 m grid square (±641 m).

B1 = NTS Claim Centroid
The minimum georeference accuracy is estimated as ½ of the hypotenuse of the 1652 m x 1542 m grid square (±1130 m).

B2 = NTS Tract Centroid
The minimum georeference accuracy is estimated as ½ of the hypotenuse of the 412 m x 386 m grid square (±282 m).

C = Community Centroid from Nova Scotia Gazeteer file
The minimum georeference accuracy is estimated as ½ of the hypotenuse of the largest distance separating any two communities in the Nova Scotia Gazeteer file for both northing and eastings (±7829 m).