Soil Science Work for Wind and Solar Power Projects in Alberta

I'm hearing a lot of talk about a busy field season coming this year in Southern Alberta for soil scientists on Pre-Disturbance Site Assessments (PDSAs) for Wind and Solar power projects regulated by Alberta Utilities Commission (AUC) under the Conservation and Reclamation Directive for Renewable Energy Operations (the REO C&R Directive). So far I've fielded questions from at least three different consulting firms planning to bid on these projects. I thought instead of saying the same thing over and over again, I'd get my thoughts pen to paper in case this is of use to my clients and colleagues in the industry.

The THEN

First and foremost, as someone who built my early career as a Soil and Reclamation Scientist, I will say that this is good for the discipline that this work exists. The importance of soil conservation to our collective food security and environmental health only increases over time, and there is no disputing that. As a result of very few opportunities for soil scientists to practice their craft in Alberta professionally over the last eight years, many have retired or left the business seeking a more stable way to put food on the table. Many of you know that I too was a casualty of the collapse of the soil science professional practice, having spent the lions' share of my early career doing field and office soil assessment ('clean' and 'dirty' dirt, but mostly 'clean' dirt) and my technical practice in Alberta disappeared almost overnight in 2014. If it wasn't for the inroads into other geographies, project management, regulatory, and operations management I had made by that point, I would have been out of work a lot sooner than I was.

For context, from 2009 through 2014, Alberta saw a 'bonanza' of soil science activity in northeastern Alberta due to the "Guidelines for Submission of a Pre-Disturbance Assessment and Conservation & Reclamation Plan" (PDA Guidelines), released by Alberta Environment in 2009 intended for use by EPEA Approval holders of an in-situ oil sands project or heavy oil processing plant. In these guidelines, the on-the-ground field work, soil and terrain mapping, and regulatory compliance documentation were highly prescriptive, and there was seemingly a never ending amount of work to be had. In this environment, I thrived. I was in my 20s spending weeks at a time in work camps, digging dozens and dozens of soil inspections almost every day during the field season throughout northeastern Alberta.

I was at the ground floor of developing the biophysical digital data collection system for soil (and by extension, later the vegetation and wildlife tools) for my former employer - I by no means assume full credit for this, but I do take some :). As schedule was driving our clients, we were often doing soil survey on areas that would never be developed, digging roughly 4 to 5 soil inspections per hectare (roughly a 45 m grid) over thousands of hectares in the summer. By 2013, my colleagues and our subconsultants and I undertook the single largest and most intense one-season soil survey probably ever done in Canada - over 2,000 ha on a 45 m grid in the Christina Lake area by Conklin, AB...roughly 8,000 soil pits - but who's counting. The revenues in field labour and equipment were in the millions of dollars per year for the big soil science shops in Alberta. Staff were flown in from all over western Canada to meet the need. The driving force of the In Situ Oil Sands soil work was the PDA Guidelines' Table 1 of inspection densities.

In contrast, throughout this time there was hardly any soil survey work being done to support the limited number of wind (and solar??) projects being developed in the Province. When there was work to be done, it was by and large desktop only and barely more than just applying the regional scale AGRASID soil polygons and making some interpretations in GIS.

In the oil and & gas collapse of 2014 through 2016, the activity and regulations came to a grinding halt - the field survey requirements in the oil sands region scaled back to something that, with the benefit of hindsight, serve the purpose just fine, but the decline in activity was crushing. That's not to say there isn't still soil work happening in the oil sands region - to be sure, there is - but the days of high-volume soil survey as I described above are long in the rear-view as far as I can tell.

The NOW

As the uptick in interests in renewable power options occurred through 2017 and has been steadily increasing, the environmental permitting regulations seem to have caught up. Alberta is now to the point where it is closing in on about 100 Wind Farms and Solar Projects in Alberta south of Oyen at some stage of regulatory approval or operations.

The current requirements in effect for managing conservation and reclamation of renewable projects are derived from AUC Rule 007, found here. The REO C&R Directive falls under this Rule 007, which outline the expectations for desktop and field-level assessment. The following table is the primary driver of the amount of effort (time and money) that will be required for the consulting scientist to complete the field and mapping components of the PDSA. From these specifications, the budgets for the entire program fall quickly into place.

There seems to be pent up enthusiasm right now for soil scientists to get back to applying their passion on the Great Plains. One can only look at Organics, Luvisols, Brunisols and Gleysols in the boreal so long before you say, "yea, I think I got it..." Not saying I don't have fond memories of it, but my knees certainly thank me that I'm not slogging through peatlands most summer days any more.

The soils of southern Alberta are fascinating in their own right. Chernozems, Solonetz, and even the elusive Vertisols occupy the landscape. The Gleysols in riparian areas and on the margins of wetlands throw curveballs with their vertic, luvic, solonetzic and humic perturbations.

The soil management implications are also quite real, with considerable consequences if they are mishandled. Southern Alberta is where most of the really saline and sodic soils are in the Province, and in combination with an arid climate, most of the land is best suited to livestock ranching rather than cropping, and large-scale irrigation is required otherwise - admixing of topsoil with strongly contrasting saline/sodic subsoil can irreversibly harm the quality of the soil for both cropland and pasture.

Topsoil ranges in colour and thickness. In the 'Brown' soil zone in the southeastern part of the Province, the difference between the topsoil and subsoil can require a discerning eye (soil zones map from Pennock and Sanborn 2015).

Irrespective, it is important that someone qualified to work with the AGRASID 4.1 Database and interpret the complex and nuanced nomenclature (and registered by ASPB or AIA) be on the team to complete desktop and field-assessment, including anticipating the scoping effort required.

One topic that isn't discussed in the REO C&R Directive (Appendix B, Section 9.1.1.3.2, "Methodology/Requirements for Deep Inspection Locations" is the requirement for "soil classification according to the Canadian System of Soil Classification" and mineral soil profile horizons properties (horizon designations). The principal diagnostic horizons that are encountered in Southern Alberta, namely the Chernozemic A and Solonetic Bn horizons, can only be verified through laboratory analysis.

Laboratory requirements to confirm the Chernozemic A horizon include:

• Total Organic Carbon (TOC) (w/w %) and Total Kjeldahl Nitrogen (TKN) (w/w %)
• Base Saturation % and Exchangeable Cations (Ca, Mg, K, Na)

Laboratory requirements to confirm Solonetzic soils include:

• Exchangeable Cations of the B horizon (the diagnostic Bn horizon has an exchangeable Ca:Na ratio of 10 or less.
• Electrical conductivity (EC) of the C horizon (usually this is at least 4mS/cm)

The landowner will likely be expecting that the proponent has a handle on the organic matter content (via the TOC and TKN), the salinity (EC) and sodicity (sodium adsorption ratio [SAR]) of the topsoil. If admixing through construction practices/soil handling degrade the soil quality, these will need to be mitigated to achieve reclamation certification. In these instances, importing topsoil is typically the only option, which can be expensive.

Because of the vast network of buried pipelines throughout Alberta, and the risks associated with striking a line while digging (even with hand tools), all the "Deep" soil inspection locations need to be swept by a line locator and Alberta One-Call (Click Before You Dig). This requires that the Deep soil inspection locations be selected well in advance. In order to do this, the desktop assessment needs to be complete (review of AGRASID 4.1) as well as a preliminary soil map identifying the polygons and probable dominant soil classification(s) within each.

Add to that, there's clubroot - the soil borne protist pathogen that threatens Alberta Canola/oilseed industry. While this is not much of a problem in southern Alberta (mainly due to the low density of oilseed fields and lower density of oil & gas pipeline activity), as of 2021 there have been clubroot observed in Newell, Rockyview, Wheatland, Starland, and Kneehill Counties and Medicine Hat. The main issue with this pathogen is its persistence in the soil and how damaging it is to crops the more intensive the oilseed cropping rotation is. The Province therefore has management planning guidelines in place to mitigate clubroot while working on public or private land, which requires strict adherence to be effective. The guidelines prescribe an equipment, vehicle, and footwear cleaning protocol using a bleach solution.

Once all of the factors discussed in this article are understood, the field effort, mapping effort and reporting effort can all be estimated pretty quickly. As we are now into early March, the scoping season is upon us for these kinds of soil projects. The soil field season in southern Alberta is from roughly mid May (depending on thaw) to late October (or when the snow starts flying).

If you are a developer looking to have PDSA's done this year, please reach out if you are interested in my help for scoping.

If you are another consultancy that is planning on bidding on these projects this year but you lack senior soil science expertise, please do not hesitate to contact me as I routinely do work for larger consultancies.

Looking forward to a good year - take care,

Collen Middleton, P.Biol., RPBio

Senior Biologist/Soil & Reclamation Scientist

Pennock, D.J. and Sanborn, P. 2015. Section 1: Soil Genesis and Geographical Distribution. From: D. Pennock, K. Watson, and P. Sanborn. Field Guide to the Soils of Western Canada. Canadian Society of Soil Science.