|
| Bedrock aquifer media |
|
| Typical value: | fractured |
| Description | There are three rock aquifers:
Wolfville, Blomidon and North Mountain |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
|
| Confinement |
|
| Typical value: | confined |
| Description | Bedrock aquifers are often confined, mainly depending on the bedrock composition, layering and fracturing, as well as the surficial sediment composition. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
|
| Groundwater storage |
| 3.56 km3 Range: [2.69 to 4.44] km3 |
| Description | Over a depth of 100 m of the Wolfville, Blomidon and North Mountain formations, a value of 3.56 km3 was estimated. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Estimation based on a fraction of total porosities estimated using image manipulation and dye injection for the Wolfville and Blomidon formations and a hypothetical percentage of interconnected fractures for the North Mountain basalts. |
|
| Surficial sediment thickness |
| 5 m Range: [0 to 60] m |
| Description | Deposits are generally thin in the upland areas (rarely exceeding 10 m), and slightly thicker in the valley (generally less than 20 m). However, they can reach 60 m in some bedrock depressions in the eastern part of the Valley. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Values mainly come from well drilling logs in the provincial databases. |
|
| Hydrogeological unit thickness |
| 100 m |
| Description | Although the three formations can be several hundreds of metres thick, the active groundwater flow seems to occur mainly within the first 100 m. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
|
| Well depth |
| 35.06 m Range: [0 to 213.36] m |
| Description | The mean well depth varies according to the geological formation and, clearly, as a function of the well type (multi-users vs residential). North Mountain : 88.7 et 53.4 m, Blomidon : 58.2 et 36.6 m, Wolfville : 74.1 et 35.1 m. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Values are based on info from two provincial databases: for wells for which a pump test was carried out (multi-users) and for residential wells. |
|
| Groundwater depth |
| 6.4 m Range: [-0.3048 to 122] m |
| Description | The mean groundwater depth varies according to the geological formation and, clearly, as a function of the well type (multi-users vs residential). There are marked vertical hydraulic gradients in the North Mountain basalts. Typical values are the following, per formation: North Mountain: 31.2 and 31.2 m, Blomidon : 7.6 and 7.5 m, Wolfville : 7.3 and 6.1 m. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Values are based on info from two provincial databases: for wells for which a pump test was carried out (multi-users) and for residential wells. |
|
| Surficial unit hydraulic conductivity |
|
| Description | Surficial sediments are mainly composed of till (Tb and Tv), glaciolacustrine (Lb.v) and glaciofluvial (Go and Bx). Associated values to these units are the following:
Tb et Tv = 3.3 e-6 m/s
Lb.v = 5e-7 m/s
Go = 1e-5 m/s
Gx = 3.1e-5 m/s |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Hydraulic conductivities have been estimated based on Guelph permeameter tests and a simplification of the Quaternary map. |
|
| Bedrock hydraulic conductivity |
| 5E-7 m/s Range: [3.8e-09 to 0.0073] m/s |
| Description | Hydraulic conductivities of these three formations are in the range of 10^-7 à 10^-6 m/s. Median values of hydraulic conductivity for North Mountain: 5.2*10^-7 m/s Blomidon: 2.8*10^-6 m/s Wolfville: 6.2*10^-6 m/s. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Based mainly on values available in the provincial pump test database. |
|
| Regional precipitation |
| 1238 mm/y Range: [952 to 1468] mm/y |
| Description | The area covered by the study receives a constant supply of precipitation annually, although the winter months are characterized by higher rainfall. Between 15% and 25% of precipitation is in snow form. Overall, the valley is slightly drier and warmer than the highlands. It is established that the valley annually receives 1 138 mm of water. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | The data are taken from 15 meteorological stations in the region or around the study area. Observations took place in a period of 5-73 years. |
|
| Regional evapotranspiration |
| 495 mm/y Range: [441 to 520] mm/y |
| Source | Regional recharge estimation using multiple methods: an application in the Annapolis Valley, Nova Scotia (Canada) |
| Methode | Values have been obtained using two methods (soil moisture balance and the hydrological model HELP). |
|
| Regional runoff |
| 356 mm/y Range: [255 to 422] mm/y |
| Description | North Mountain : 285 and 444 mm/y, Blomidon : 276 and 444 mm/y, Wolfville : 250 and 434 mm/y et pour l'ensemble de la vallée : 300 to 425 mm/y |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Values have been obtained using three methods (stream hydrograph separation, soil moisture balance and the hydrological model HELP). Only the last two methods provide values per formation. |
|
| Regional recharge |
| 183 mm/y Range: [58 to 444] mm/y |
| Description | The values presented here correspond to bedrock recharge. A significant portion of the estimated infiltration flows as subsurface runoff (hypodermic flow) and thus, is likely to reach streams before any ""window"" to the bedrock. The Wolfville, Blomidon and North Mountain formations represent the most important recharge areas of the sector. |
| Source | Regional recharge estimation using multiple methods: an application in the Annapolis Valley, Nova Scotia (Canada) |
| Methode | Values have been obtained using four methods (hydrograph separation, soil moisture balance, the hydrogeological model FEFLOW and the hydrological model HELP). Values were obtained per formation for the last three methods. |
|
| Regional discharge |
|
| Description | Rivers in the 5 watersheds (e.g., Annapolis and Cornwallis rivers) corresponds to discharge zones. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
|
| Hydrogeological unit potential |
|
| Typical value: | high regional - medium regional |
| Description | The aquifer potential is good or variable for these three formations. The best would likely be in the Wolfville Formation. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
|
| Aquifer vulnerability |
| 4 Range: [1 to 6] |
| Typical value: | Moderate |
| Description | Vulnerability to surface contamination for the Wolfville, Blomidon and North Mountain formations varies widely from extremely low to high, mainly as a function of the surficial sediment cover. On average over the entire formation, these formations show values of low and moderate vulnerability. The Wolfville Formation would be the most vulnerable of the three. |
| Source | CANADIAN GROUNDWATER INVENTORY: REGIONAL HYDROGEOLOGICAL CHARACTERIZATION OF THE ANNAPOLIS VALLEY AQUIFERS |
| Methode | These results are based on vulnerability categories established after employing the well-known DRASTIC index method.
Based on vulnerability category
Category DRASTIC index value Description
1 1 to 79 Extremely low
2 80 to 99 Very low
3 100 to 119 Low
4 120 to 139 Moderate
5 140 to 159 Moderately high
6 160 to 179 High
7 180 to 199 Very high
8 200 to 230 Extremely high |
|
| Groundwater Quality |
|
| Description | Groundwater quality is generally good, but nitrate concentrations are of concern in several areas. In addition, some aesthetical criteria, such as those for iron and manganese, are often exceeded. |
| Source | Canadian groundwater inventory: Hydrogeological atlas of the Annapolis Valley, Nova Scotia |
| Methode | Data came mainly from provincial databases, but also from a federal database (EC), from Kings County, from a local organisation (CARP) and from our own fieldwork. |
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