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K-State Agronomy eUpdates

Department of Agronomy

Kansas State University

1712 Claflin Rd.

2004 Throckmorton PSC

Manhatan, KS 66506

785-532-6101

agronomy@ksu.edu

Extension Agronomy

Remediating soils affected by brine spills

Brine spills sometimes occur on agricultural lands, either from nearby oil and gas operations or some other cause. When a brine spill occurs, producers and landowners will need to report the spill, assess the impact of the spill, and find out what it will take to remediate the effects and return the soil to near-normal conditions.

Reporting a brine spill

The source of the brine determines which state agency needs to be contact to report the spill. The spiller/operator is responsible for reporting the spill and can use the 24/7 Kansas Spill Reporting hotline 785-291-3333 or contact the appropriate district office of the Kansas Corporation Commission (KCC) or the Kansas Department of Health and Environment (KDHE).

The KCC handles spills associated with past or present oil or gas lease (drilling, production, etc.) activity. Spill reporting requirements are as follows:

  • If the spill has reached or threatens to reach surface water or threatens to impact ground water the operator must report the spill immediately upon discovery or knowledge [K.A.R. 82-3-603 (b) (1)].
  • All other spills shall be reported no later than the next business day following the date of discovery or knowledge of the spill [K.A.R. 82-3-603 (b) (2)] except those exempt, very minor spills, that occur as a result of normal and prudent operations [K.A.R. 82-3-603 (b) (3)].
  • The operator is also obligated to make a good faith effort to notify the landowner or owner’s representative within five business days following the discovery or knowledge of any spills or escapes that are required to be reported [K.A.R. 82-3-603a (a)].

All other brine spills including those resulting from the off lease transport of brine produced as a result of oil and gas production are reported to the KDHE Bureau of Environmental Remediation via the 24/7 Kansas Spill Reporting hotline 785-291-3333

Landowners with questions or concerns about brine spills on oil and gas leases, or failure to be notified by a lease operator of a spill should contact their appropriate KCC district office (http://www.kcc.state.ks.us/contact.htm).

Recording the location

First, define the affected area, using a tape measure or by pacing. It’s also a good idea to record the latitude and longitude coordinates for the spill. If the spill is large, multiple points could be recorded. A simple way to do this is by using the Google Maps app, which is free to download on smartphones. By placing your finger on the screen, you can drop a pin at your location, and then edit the label. For example, you could drop a pin and edit it to say “north edge of spill.”  That pin will be visible to you when you log in to Google Maps or Google Earth on your computer. You can also share that pin by email, text, etc. with others.

Soil sampling after a brine spill

Soil samples should be collected from affected and non-affected areas after a spill. For help with soil sampling, you could contact your local Extension office, a crop consultant, or an environmental consultant. Local Extension offices have Agriculture and Natural Resource agents who are knowledgeable about how to collect proper soil samples, and they have access to soil probes, which can be lent out to landowners.

A good sampling strategy is to sample to a minimum depth of 12 inches, breaking the core into 0-6 and 6-12 inch segments (you’ll want to take 2 buckets to the field, one where you can place the 0-6 and one for the 6-12 inch depth). Collect 10-15 cores, split them into the two depths, and composite the sample. Place the soil into a paper or plastic bag, and label the bag with the sampling location, depth sampled, and other pertinent information. Record the sample names on a laboratory submission form. Soil sample bags and KSU Soil Testing Laboratory submission forms are also available from your local Extension agent.

How many samples should be collected in a spill area? It depends on the size of the spill. If the affected area is 100 square feet on a flat area, one sample comprised of the 10-15 cores should be sufficient. If the spill affects thousands of square feet, and runs downslope, multiple soil samples might be needed.

Samples should also be collected from outside the spill area, but nearby, on a similar slope position. These will be used to determine the pre-spill soil properties.

Analyses to run on soil samples

The KSU Soil Testing Laboratory has a Salt Alkali package that measures the electrical conductivity, the exchangeable sodium percentage, and the soil pH. This determines if the soil is saline, sodic, or saline-sodic. For more details on testing, refer to https://webapp.agron.ksu.edu/agr_social/eu_article.throck?article_id=87 

Table 1. Salt-affected soil classification

Classification

Electrical conductivity (EC) (mS/cm)

Soil pH

Exchangeable sodium percentage (ESP)

Soil physical condition

Saline

>4

<8.5

<15

Normal

Sodic (alkali)

<4

>8.5

>15

Poor

Saline-sodic

>4

<8.5

>15

Normal

 

After receiving lab data, the landowner can determine a course of action.

If the soil is saline: If the electrical conductivity values exceed 4 ms/cm, but the ESP is less than 15, the soil contains high levels of salts, which could be sulfates and/or chlorides of calcium and/or magnesium. Saline soils can be reclaimed by flushing with large amounts of high-quality (low salt) water. The leaching water requirements will be explained in more detail at the end of this article.

If the soil is saline-sodic or sodic: To improve the soil structure, the sodium needs to be replaced with calcium, and this is done with gypsum, CaSO4.2H2O, which is very soluble. The rate of gypsum application is 1.7 tons gypsum per millequivalent (meq) of exchangeable sodium, which is provided with the Soil Salt Alkali laboratory report. After the gypsum is added, large amounts of water will need to be added to flush out the salts. It’s important in a saline-sodic soil to treat with gypsum prior to starting an aggressive leaching program, since the physical properties of a saline-sodic soil are generally good. If one cuts off the source of the salts and leaches the free salts from the soil first, the sodium in the soil will destroy the physical properties, making leaching extremely slow and difficult. So make sure for either a saline-sodic or a sodic soil to add gypsum before leaching.

Calculating leaching water requirements for saline soils

From the K-State Research and Extension publication, Managing Saline and Sodic Soils in Kansas, by Lamond and Whitney (1992), the following recommendation is often used: 8 to 10 inches of leaching water may be necessary to remove 70 percent of total salts for each 12 inches of soil to be leached.

Example:

Soil samples collected within a brine spill area had an average electrical conductivity (EC) of 24 mS/cm, receiving a salinity ranking of Very Excessive. The sample taken nearby outside the spill had an EC of 1.5 mS/cm, rated as Low Salinity.

Following the Lamond and Whitney approach:

If 8-10 inches of leaching water is applied to 1 foot of affected soil, that would reduce the EC from 24 to 7.2 mS cm-1 which is still Highly Saline.

If you applied another 8-10 inches of leaching water to that same foot of soil, the EC would now be 2.2 mS cm-1 which classifies as Moderately Saline.

If you applied another 8-10 inches of leaching water, you could reduce the EC to less than 1 mS cm-1 which would classify as having Low Salinity.

The leaching requirement, therefore, is 24-30 inches of water to leach the salts out of one foot of soil. It is recommended that the salts be leached out of the upper 2 feet of the soil profile, so in this example, 48-60 inches (4-5 feet) of leaching water should be applied. In wetter regions, the lower end of the range can be used, and in drier areas, the upper end of the range should be applied.

A second way to calculate the leaching water requirement is from the University of California-Davis publication, called Agricultural Drainage and Salinity by Hanson et al. (2006).

 

Equation:

 

Where: Dw = depth of water infiltrated (feet)

            Ds = depth of soil to be reclaimed (feet)

            k = 0.45 for organic soils, 0.30 for fine-textured soils, 0.10 for coarse-textured soils

            ECef = final soil salinity desired

            ECei = initial soil salinity

 

So to reduce the EC from 24 to 1.5 mS cm-1, the water requirement for a fine-textured soil (such as a silty clay loam) would be:

 

Which equals 4.8 feet of water to reclaim one foot of soil, or 7.2 feet of water to reclaim two feet of soil. 

 

Despite the fact that the two approaches give different values, they illustrate that a great deal of water must be applied to leach soluble salts from the upper two feet of the soil profile. To reiterate, these values were calculated for a silty clay loam soil, and using example laboratory data. Calculations must be performed using actual laboratory testing data, and using the correct k factor for the soil type. The greater the EC value, the more water is required. Soils that contain more clay will require more leaching water than a sandy soil.

For more information:

To report any kind of spill 24/7, contact the Kansas Spill Response Program at 785-291-3333 http://www.kdheks.gov/spill/ 

For more detailed information on saline and sodic soils, see K-State Extension publication MF-1022 at: http://www.ksre.ksu.edu/bookstore/pubs/MF1022.pdf

Clean up guidelines for brine spills:
http://www.kcc.state.ks.us/conservation/cleanup_brochure.htm

 

DeAnn Presley, Soil Management Specialist
deann@ksu.edu

Peter Tomlinson, Environmental Quality Specialist
ptomlin@ksu.edu

Dorivar Ruiz Diaz, Nutrient Management Specialist
ruizdiaz@ksu.edu