1999-08-23_HYDROLOGY - M1999051 - Laserfiche WebLink

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August 1999 C\ 99V2057 2057rin.xl TABLE 1 RISK ASSESSMENT SUMMARY Leaks Operator Error 1) Mechanical failure of gaskets, valves or other pipeline fittings Subsidence - Negligible Hazard Groundwater - Negligible (alluvial well) Soil - Low Hazard Surface Water - Negligible Hazard Initiating events and likelihood: Medium likelihood, annual failures have occurried at other similar facilities. Magnitude of exposure: Low exposure, assuming a leak rate of 10 gpm for a maximum of 8 hours total volume of pregnant soda liquor is 4,800 gallons. Duration of exposure: Low exposure because of rapid recognition due to visual inspection every 8 hours and camera monitoring along most of the length of pipeline. Pathways: very low risk due to drainage control and collection, rapid precipitation of approximately 70 percent of the sodium bicarbonate as the solution cools, and local soil uptake of the moisture minimizing runoff. Environment at risk: Topsoil will be removed and stockpiled in a safe location for reclamation outside the bermed pipeline corridor. The only environment at risk is the foundation material along the pipeline. Initiating events and likelihood: Negligible likelihood, due to 5 year life of the pipeline and facilities. Corrosive failures have occurried at other similar facilities after 10 years of operation. Magnitude of exposure: Low exposure, assuming a leak rate of 10 gpm for a maximum of 8 hours total volume of pregnant soda liquor is 4,800 gallons. Duration of exposure: Low exposure because of rapid recognition due to visual inspection every 8 hours and camera monitoring along most of the length of pipeline. Pathways: very low risk due to drainage control and collection, rapid precipitation of approximately 70 percent of the sodium bicarbonate as the solution cools, and local soil uptake of the moisture minimizing runoff. Environment at risk: Topsoil will be removed and stockpiled in a safe location for reclamation outside the bermed pipeline corridor. The only environment at risk is the foundation material along the pipeline. 2) Pipeline corrosion and leakage Subsidence - Negligible Hazard Groundwater - Negligible Soil - Very Low Hazard Surface Water - Negligible 1) Accidental Release due to upset conditions or operation errors Subsidence - Negligible Hazard Groundwater - Negligible Hazard (alluvial well) Soil - Very Low to Medium Hazard Surface Water - Negligible Low hazard Initiating events and likelihood: Medium likelihood, failures have occurried at other similar facilities. Magnitude of exposure: Medium risk due to rapid recognition of the discharge. The pipeline will be placed in a bermed corridor that drains to a lined collection pond. Conservative assumptions for leakage volume 20 mins. 400 gpm results in a maximum of 8,000 gallon spill. Duration of exposure: Medium exposure due to rapid recognition of the pipe rupture allowing system shut down. Most of the length of the pipeline will be monitored by camera, and the system will have automated warning sirens when there is a pressure difference between the wells and plant. Pathways: very low risk due to drainage control and collection, rapid precipitation of approximately 70 percent of the sodium bicarbonate as the solution cools, and local soil uptake of the moisture minimizing runoff. Environment at risk: Topsoil will be removed and stockpiled in a safe location for reclamation outside the bermed pipeline corridor. The only environment at risk is the foundation material along the pipeline. Low consequences due to low potential hazard to soils and low magnitude and duration for exposure. The pathway for exposure is negligible and the environment at risk is within the industrial disturbance area. Low consequences due to low potential hazard to soils and low magnitude and duration for exposure. The pathway for exposure is negligible and the environment at risk is within the industrial disturbance area. Very low consequences due to very low risk pathways for exposure. Also the environment at risk is within the industrial disturbance area. Negligible to low risk even with Medium likelihood and low soil hazard due to the environment at risk being in the industrial disturbance, and negligible exposure risk due to the pathway for exposure Recommended Mitigation: Emergency Spill Response Plan; Employee Training Program; Well Defined Action Levels for Agency Reporting and Remediation; Employee Environmental Protection Incentive Program i Negligible risk even with low soil hazard due to negligible likelihood, the environment at risk being in the industrial disturbance, and negligible exposure risk due to the pathway for exposure. Very low risk due to the industrial nature of the environment at risk, and very low risk pathway for exposure as the release would be within a bermed area draining to a lined pond thereby minimizing potential for exposure. Recommended Mitigation: Emergency Spill Response Plan; Employee Training Program; Well Defined Action Levels for Agency Reporting and Remediation; Employee Environmental Protection Incentive Program Footnotes to Table 1: Risk Assessment Components: Potential Failure Mechanisms: All identified potential mechanisms are included, regardless of likelihood of occurrence Hazard Assessment: An assessment of "what can happen ?" ranked according to risk to the environment (see Table 2) Exposure Assessment: Assessment of the likelihood and extent of any exposure. Consequence Assessment: An evaluation of the consequence of any exposure, regardless of how likely it is. Risk Characterization: An evaluation of the overall risk to the environment of the identified failure mechanism, based on the evaluation of hazard, exposure and consequence. 3 of 5 Golder Associates 993 -2057