OHA Drinking Water Services
OHA Drinking Water Services
Contact Report Details
PWS ID: OR41 00585
PWS Name: OCEANSIDE WATER DISTRICT
 
Who Was Contacted: David Nordman
Contact Phone: 503-842-6462 (Email address hidden)
Contact Date: 08/24/2023
Contacted By: HOFELD, EVAN (DWP)
Contact Method/Location: Email
 
Assistance Type: WATER QUALITY ALERT RESPONSE
Reasons: Disinfection Byproducts
 
Details: On 8/24/23 I received an alert for a high TTHM result of 0.1045 mg/l sampled on 8/15/23 (HAA5 was 0.0352 mg/l). I calculated the Locational Running Annual Average (LRAA) and Operational Evaluation Level (OEL) for TTHM and determined that the OEL exceeded 0.080 mg/l for TTHM, which requires the system to complete an OEL report within 90 days. TTHM LRAA and OEL levels were calculated using sample results from the most recent 4 quarters as follows: (0.1045 + 0.0436 + 0.0765 + 0.0424) / 4 = 0.06675 mg/l TTHM LRAA. (2 x 0.1045) + 0.0436 + 0.0765) / 4 = 0.082275 mg/l TTHM OEL. I e-mailed David Nordman the calculated results and OEL report template. The system previously exceeded the TTHM OEL in 3rd quarter 2022 and completed an OEL report at that time (recvd 10-28-22) citing an algal bloom in the source water (SRC-AA Short Creek). As a membrane plant with coagulation, I recommended they monitor UVT (they have a portable RealTech REAL UV254 meter with measures UVT) and dose coagulant accordingly using a dose response curve and offered to assist with developing that curve. 10/29/23 Update - I received the OEL report from David Nordman, which indicated that they had an algal bloom in the source water and telemetry issues allowed the Capes reservoir level to drop, which may have stirred up sediment in the bottom of the tank when it was rapidly refilled. They are planning on having all the reservoirs cleaned to remove sediment and the intake reservoir cleaned out to help alleviate algal blooms. They are also looking at using a stronger muriatic acid as a cleaning agent for the membranes (they currently use citric acid).
 
Associated Alerts: DBP-23 - 08/24/2023 - TTHM


More information for this water system: SDWIS ID 3980
System Info  ::  Report for Lenders  ::  Alerts  ::  Violations  ::  Compliance & Enforcement  ::  Contacts & Advisories  ::  Site Visits  ::  Public Notice
Coliform Summary  ::  Coliform Results  ::  Coliform Schedules  ::  LT2  ::  GW/GWUDI Source Details  ::  Plan Review  ::  Annual Fee
Chemical Summary  ::  Chemical Results  ::  Chemical Schedules  ::  Chemical Schedule Summary  ::  Arsenic RAA  ::  Cyanotoxins  ::  PFAS
Lead & Copper  ::  DBP Sample Sites  ::  FANLs  ::  MRDL  ::  GWR 4-Log  ::  Turbidity  ::  SWTR  ::  LRAA
Corrosion Control has moved to the Lead & Copper page.
Information for all water systems:
Water System Inventory  ::  Water System Surveys  ::  Outstanding Performers  ::  Treatment Plant Inspections  ::  Treatment  ::  Plan Reviews
Alerts  ::  Violations  ::  Compliance & Enforcement  ::  Deficiencies  ::  System Scores  ::  Exceedances  ::  Public Notices  ::  Service Lines
Water Advisories  ::  Contact Reports  ::  Cyanotoxins  ::  PFAS  ::  Post-wildfire VOCs  ::  Fluoride  ::  Certification List
Introduction  ::  Data Search Options  ::  Water System Search  ::  DWS Home  ::  DWS Rules
Need help? Email Drinking Water Services for assistance.Staff/Partner Login