API Publ 4758:2006 pdf download
API Publ 4758:2006 pdf download.Strategies for Addressing Salt Impacts of Produced Water Releases to Plants,Soil, and Groundwater.
Using the Planning Model
Results of this modeling are combined with other site-specific Information to determine the potential elf ects on ground water.
To use the Planning Model. perform the foaowing steps:
Step 1 Estimate Mass of Chloride using volume and chloride concentration of a produced water release, OR
Estimate Mass of Chloride using the area of produced water release (area of affected soil) and the chloride concentration of the soil (page 10)
Step 2: Estimate Chloride Loadr.rca iate to Groundwater using the Annual Preciç:Ntation, (page 11)
Step 3A: Estimate Increase in Chloride Concentration in Groundwater at the Release Point using the width of Ihe release area. (page 12)
Step 38: Refine the estimate from Step 3A using site-specific information (either the site location, or more detailed hydrogeologic info), page 13)
Step 4: (Optional) Estimate the Increase in Chloride Concentration in Groundwater ala Downoradient Point using the detance from the release area (and other parameters). (page 14)
Key assumptions and limitations of the Planning Model Include: 1) salts are mixed evenly throughout the soIl; 2) the percentage of the rainfall that infiltrates through the soil to groundwater is proportional to the amount of rainfall; 3) the recharge rate is the 80” percentile 01 recharge rates from data compiled from API Publication 4643:4) aJmost all the salts in affected soils can be flushed out with 12 inches of recharge (from API 4663); 5) no capillary effects. evaporation, or other transport processes except advection. mixing. and dispersion in the saturated zone are present; 6) no density effects are assumed in transport of chloride in groundwater; 7) salt is mixed throughout the water-bearing unit: 8) a 2x safely factor is assumed: and 9) potential impacts only apply to the uppermost water-bearing unit, and NOT to deeper, regional aquifers. When applied to site conditions presented in API Publication 4734, the Planning Model was more likely to show higher chionde concentrations in groundwater than chloride concentrations predicted by HYDRUS. a much more sophisticated leaching model.
Other Methods
Other approaches can also be used to provide more accurate estimates of chlonde migration. Key resources include:
• API Publication 4734: In this Study, the authors performed several hundred computer simulations with the HYDRUS model to determine the sensitivity of groundwater underlying a produced water release to various factors such as release volume, chloride concentration of the produced water, depth to groundwater. soil type, rainfall and hydrology of the area, and other factors. Review of this document can provide additional information regarding the impact of produced water releases on groundwater.
• More Detailed Computer Models: Models such as VADSAT or HYORUS can be applied to investigate potential groundwater impacts from produced water releases.
• Site InvestIgatIon: A groundwater site investigation Involving the collection of groundwater samples from monitoring wells or direct push sampling techniques can show if a produced water release has actually affected groundwater at a given site.
Factors That May Influence Remediatlon of Saltwater Releases
For the purposes of this guIde, the principal objective of groundwater remediation is to maintain the beneficial use of the groundwater resource. However. remediation of saltwater releases can be influenced by a variety of non-teciwlical factors that are not directly addressed in this guide. These non-technical factors include (API Publication 4663):
• Landowner claims • Reduction of long-term liabilities
• Lease agreements • Company policies
• Federal, state, and local regulations
How Salt Can Affect Plants
Water present within the soil pores is subject to several forces related to: i) the soil solid phase: ii) the dissolved salts: and iii) the
gravitational field. Plants work against the capillary tension of water within the soil pores in order to draw in water. An increase in the
TDS of the soil pore water increases the osmotic effect, thereby increasing the force a plant must exert to extract water from the soil.
This can cause plants to go into drought stress even though a substantial amount of water may still be present in the soil.
Plants are more sensitive to salinity during germination than in later stages of growth. Sprigging, sodding, or transplanting of plant materials is a way to avoid the sensitivity of the seedling stage.
Symptoms of Plant Stress Caused by Salt
Excessive soil salinity can result in barren spots, stunted vegetative growth with considerable variety in size, and a deep blue-green foliage (USDA. 1954). Plants that are stunted due to low fertility are usually yellow-green, while those stunted due to elevated salinity are characteristically blue green. The bluish appearance is the result of an unusually heavy waxy coating on the surface of the leaves. and the darker color is due to increased chlorophyll content. Some plants may develop dead areas or tipburn or exhibit cupping or rolling of the leaves.