Alberta West News: Compile a report on Total Dissolved Solids for wells in this database

Now I'll compile a comprehensive report based on the information gathered about TDS in Alberta's water well database.

Total Dissolved Solids in Alberta Water Well Database: A Comprehensive Report

The Alberta Water Well Information Database (AWWID) contains extensive water quality data, including Total Dissolved Solids (TDS) measurements from approximately 500,000 water well records across the province. This database, maintained by the Groundwater Information Centre, provides critical insights into groundwater quality patterns and serves as a foundation for water resource management and regulatory decisions.alberta+1

Regulatory Framework and Standards

In Alberta, groundwater classification is based on TDS concentration. The provincial definition of saline groundwater is water containing greater than 4,000 mg/L TDS. Water with TDS less than or equal to 4,000 mg/L is considered non-saline or "fresh" groundwater and receives regulatory protection. This threshold is critical for determining the Base of Groundwater Protection (BGWP), which establishes the depth at which cementing and other well construction requirements apply.mightypeacewatershedalliance+2

The aesthetic guideline for drinking water in Canada is set at 500 mg/L TDS. Water with TDS below 600 mg/L is generally considered to have good palatability, while concentrations above 1,200 mg/L are unpalatable to most consumers. At concentrations above 500 mg/L, excessive scaling in water pipes, heaters, and appliances may occur.canada+2

Extent of TDS Exceedances in Alberta Wells

Analysis of baseline water well testing data reveals that 93% of all records in the database (7,792 wells) indicate TDS values exceeding the 500 mg/L drinking water guideline. This high percentage reflects the naturally mineralized character of Alberta's groundwater, particularly in areas with high evaporation rates and specific geological conditions.open.alberta

While over 90% of Alberta's groundwater wells exceed one or more drinking water quality guidelines, most of these problems are not health-related but rather aesthetic issues related to palatability, hardness, and scaling.open.alberta

Geographic and Regional TDS Distribution

TDS concentrations in Alberta groundwater vary dramatically by region, reflecting differences in climate, geology, and aquifer type:

Climate-Driven Patterns

Eastern and Southern Alberta: In east-central and southern Alberta, where annual precipitation ranges from 25-40 cm (10-16 inches) and evaporation rates are high, TDS concentrations average approximately 2,500 parts per million (ppm). The low precipitation and high evaporation lead to concentration of dissolved minerals as groundwater approaches the surface and deposits salts in soil, which then redissolve into infiltrating precipitation.agriculture.alberta+2

Western Alberta: In western Alberta, where annual precipitation exceeds 45 cm (18 inches) and evaporation rates are lower, groundwater in surficial deposits contains less than 800 ppm TDS. This pattern reflects greater dilution from increased recharge.open.alberta+1

Major Aquifer Systems

Paskapoo Formation: The Paskapoo Formation, which supports more groundwater wells than any other aquifer system in the Canadian Prairies (approximately 200,000 wells drilled, with 70,000 considered active), shows TDS values ranging from 375 to 2,500 mg/L with an average of 1,000 mg/L. The formation displays a significant east-west gradient:members.cgs+1

Western portions: TDS typically less than 450 mg/Lcrossconservation
Southeastern portions: TDS greater than 750 mg/L and up to 1,500 mg/Lcrossconservation
Overall range: Mainly fresh with TDS less than 2,000 mg/Lopen.alberta

Edmonton-Calgary Corridor Aquifers: The Edmonton-Calgary Corridor, which has been extensively characterized by the Alberta Geological Survey, contains groundwater data from more than 20,000 chemical analyses. The corridor includes major bedrock aquifers such as the Paskapoo, Horseshoe Canyon, Belly River, and Bearpaw formations, as well as surficial sediments aquifer.ags.aer+2

Clearwater Hydrostratigraphic Unit: In the Clearwater formation, measured TDS values range from 278 mg/L to approximately 43,000 mg/L, with the unit predominantly acting as a weak aquitard rather than a productive aquifer.ags.aer

Grande Prairie-Beaverlodge Area: Over most of this west-central Alberta region, groundwater to a depth of 450 feet (137 meters) has TDS contents generally less than 1,500 mg/L. However, in the northeastern portion near Smoky Group shales, groundwater quality is poorer, with TDS concentrations in bedrock exceeding 2,000 mg/L.ags.aer

Edson Area: Total dissolved solids in bedrock waters range from 200 to 1,000 mg/L, with a maximum TDS in drift waters of 700 mg/L.ags.aer

Depth Relationships and Aquifer Type

Water quality varies systematically with depth and aquifer type, following predictable geochemical patterns:

Shallow versus Deep Aquifers

Shallow Aquifers: Shallow groundwater aquifers have lower TDS concentrations than deeper aquifers because water has less contact time with aquifer materials and travels shorter distances. However, shallow wells typically have higher levels of calcium, magnesium, and iron, making the water "hard". These elevated mineral concentrations result from the interaction with surficial materials.agriculture.alberta+1

Deep Aquifers: Deeper aquifers typically produce more mineralized water with higher TDS because groundwater travels longer distances and has extended contact time with geological formations. Deep wells tend to have higher sodium levels and lower hardness, producing "soft" water. The median concentrations of calcium, potassium, and sulfate, as well as TDS, decrease with depth in some systems, while carbonate, chloride, and fluoride increase with depth.open.alberta+2

Surficial versus Bedrock Aquifers

Surficial Deposits: Surficial aquifer TDS varies widely but is often influenced by overlying glacial materials. In areas with Cordilleran till deposits (western regions), groundwater contains lower TDS and is typically characterized by Ca-HCO₃ chemistry. Surficial groundwater TDS typically ranges from less than 500 mg/L to more than 3,000 mg/L, locally exceeding 6,000 mg/L.open.alberta+2

Bedrock Aquifers: In Alberta, 84% of wells draw from bedrock aquifers while 16% draw from unconsolidated surficial deposits. Bedrock groundwater generally has TDS ranging from 1,000 to 2,000 mg/L in many areas. Water from bedrock is resident for longer periods and influenced by different surrounding materials compared to surficial aquifers.waterportal+2

Water Chemistry and TDS Components

The composition of TDS varies by location and aquifer, but major ions consistently include:

Primary Contributors:

Sulfate (SO₄²⁻): Highly variable across Alberta, with 22% of samples exceeding 500 mg/L. Concentrations range over three orders of magnitude (1 to >1,000 mg/L) in formations like the Paskapooalbertainnovates+1
Sodium (Na⁺)
Calcium (Ca²⁺)
Magnesium (Mg²⁺)
Chloride (Cl⁻)
Bicarbonate (HCO₃⁻)

Water Types by Region:

Shallow bedrock: Ca-Mg-HCO₃-CO₂ type
Moderately deep to deep bedrock: Na-K-HCO₃-CO₂ type
Various depths with sulfate influence: Mixed types dominated by sulfatesags.aer

In south-central Alberta shallow groundwater, the average TDS is 1,037 mg/L, with most samples classified as Na-HCO₃-SO₄ water type and average sulfate concentrations of 185 mg/L.sciencedirect

Irrigation District Water Quality

Alberta's irrigation districts have been extensively monitored for water quality, including TDS. Overall water quality for irrigation is rated as "good" or "excellent" for most source waters. However:open.alberta

Return flows generally have poorer quality than source watersopen.alberta
Many districts show significantly greater salinity and major ion concentrations in return flows compared to source watersopen.alberta
TDS levels below 700 mg/L are considered safe for irrigation, while levels between 700 and 1,750 mg/L are possibly safe, and levels above this range are considered hazardousagric.gov

Database Characteristics and Data Quality

The AWWID system receives approximately 3,000 to 5,000 new well reports annually. The majority of modern drilling reports are submitted electronically and published within an hour, though paper submissions may take longer to appear.groundwater.alberta+3

Data quality considerations include:

Chemical analysis reports are only available up to 1986 in the main databasestarlandcounty+1
More recent water chemistry data comes from various programs including baseline water well testing, the Groundwater Observation Well Network (GOWN), and specialized studiesags.aer
The Alberta Geological Survey has compiled and quality-checked over 20,000 chemical analyses for major mapping projectsags.aer
Statistical summaries include median, minimum, maximum, quartile values, and representativity classifications by quarter township for 15 groundwater quality parameters including TDSags.aer

Applications and Uses

The TDS data from AWWID supports multiple applications:

Hydrogeological Mapping: Regional TDS distribution maps have been created for numerous hydrostratigraphic units using geostatistical techniques (kriging) with AWWID dataags.aer+4
Regulatory Compliance: Determining the Base of Groundwater Protection and establishing well construction requirementsaer
Water Resource Planning: Assessing groundwater quality for drinking water, irrigation, and livestock wateringghostlake
Baseline Monitoring: Establishing pre-development conditions for energy projects, particularly coalbed methane operations where over 6,000 baseline water well tests were conducted between 2006 and 2008members.cgs
Research and Resource Characterization: Understanding regional groundwater geochemistry patterns and controls on water qualitysciencedirect+1

Conclusions

Alberta's water well database reveals that the province's groundwater is naturally highly mineralized, with 93% of wells exceeding the 500 mg/L aesthetic guideline for TDS. This reflects the semi-arid climate, particularly in eastern and southern regions, combined with the influence of diverse geological formations. TDS concentrations range from less than 300 mg/L in some western areas to over 40,000 mg/L in certain deep formations, with typical values between 1,000 and 2,500 mg/L depending on location, depth, and aquifer type. The AWWID database, containing 500,000 well records, provides essential information for water resource management, regulatory oversight, and scientific understanding of Alberta's groundwater systems.

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Compile a report on Total Dissolved Solids for wells in this database