Water Environment Services

Water Environment Services

BMP Sizing Tool

WES, in cooperation with other local jurisdictions, has developed a BMP Sizing Tool to assist developers in meeting flow duration matching requirements customized to Clackamas County conditions. The Tool sizes facilities so that post-development peak flow durations will match the pre-development peak flow durations ranging from 42% of the 2-year to the 10-year flows, as determined by HSPF continuous rainfall model simulation.

The BMP Sizing Tool automates some of the required calculations to support BMP sizing and design for a specific set of stormwater management facility types (See Section 9.0 of User's Guide).

Responses to frequent BMP Sizing Tool questions can be found in Appendix A of the User's Guide, including:

  • Rain gardens, stormwater planters, vegetated swales, and infiltrators are referred to as LID facilities. The BMP Sizing Tool uses different methods for sizing LID facilities (Section 9.2) and detention ponds (Section 9.3).
  • If there are multiple types of post-development surface covers on the site, each of the areas should be delineated separately and entered separately in the BMP Sizing Tool under the Discharge Management Areas tab. 
  • Predevelopment surface conditions should reflect historical conditions (i.e., grass or forest). Even when the pre-development condition is impervious surface, it should be included in the BMP Sizing Tool as grass or forest.
  • The BMP Sizing Tool sizes facilities to manage the 10-year peak flow (based on continuous simulation.) However, WES design standards require conveyance systems to be sized for the peak flow from a 25-year, 24-hour design storm.
  • The BMP Sizing Tool is based on LID principles, including the concept of prioritizing small, distributed surface vegetated facilities. As a guideline, it is recommended that the area draining into a single BMP facility should not exceed approximately 10 acres.

Resources

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Watershed Health Education Program

The Watershed Health Education Program educates youth about the importance of protecting our watersheds. The program makes it possible for local teachers and their students to get out of the classroom and into the field, where they gain hands-on experience making assessments, restoring streamside habitats, and studying the factors that determine healthy rivers and streams. These students then share their knowledge with friends, family and the broader community through presentations and activities, making an even bigger impact on protecting public health and the environment. WES works with partners to educate K-12 students in our community, and some projects span multiple years. To learn more about this program and projects, please contact Gail Shaloum at gshaloum@clackamas.us.

Educational Opportunities

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Stormwater Construction Projects

WES protects watershed health and water quality in communities within northern Clackamas County. WES plans to upgrade several stormwater systems in the community.

This stormwater system improvement work is expected to begin in late August or early September and may take up to four weeks and cause minor traffic disruptions. On weekdays, work hours will be limited to 7 a.m. to 6 p.m. If work is necessary on a weekend, the schedule would be 8 a.m. to 5 p.m.  Diamond Court

  • New stormwater pipe 
  • New stormwater treatment manhole
  • Removal of downed trees and vegetation 
  • New maintenance access road

Diamond Court

William Otty Road

  • Removal and replacement of an existing storm drain
  • Add additional storm drain
  • Removal and replacement of storm pipe and catch basin in William Otty Rd.
  • Add maintenance access

William Otty Road

Sunny Way

  • New stormwater pipe 
  • New stormwater treatment manhole
  • Removal of trees and vegetation 
  • Repair pedestrian trail (trail access from Sunny Way will be closed during construction)

Sunny Way

Contact Us
Department Staff
Leah Johanson
Civil Engineer, Senior
503-742-4620
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Report a Spill or Leak

Report sewer or stormwater problems or concerns, such as a sewer spill or illegal dumping into a storm drain.

Monday to Thursday
7:30 a.m.-12 p.m. & 1 p.m.-5 p.m.
503-742-4567
Weekends and after hours503-655-8211
Email 
Monday to Thursday
7:30 a.m.-12 p.m. & 1 p.m.-5 p.m.
wescustomerservice@clackamas.us
Emergency situation? Please use our phone numbers.

Please include the following information:

  • Address or nearest cross street
  • Description of problem
  • Your name
  • Your contact information, including phone number and email address

Your name and contact information will be considered to be submitted in confidence, and the county will not disclose your name or contact information except as required by law.

Thank you for helping us to protect public health and the environment!

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Industrial Pretreatment

As a result of a federal government (Environmental Protection Agency) mandate, we implemented an industrial pretreatment program in 1986.

Direct services provided by the program include industrial permitting, facility inspections, sampling, laboratory analysis and enforcement. Indirect services include: development of local limits, updating rules and regulations, load investigations, responding to regulatory authorities and conducting industrial surveys.

Our staff inspects the industrial pretreatment processes of businesses to eliminate illegal discharge of harmful chemicals into the sewage treatment process and collects wastewater samples to ensure industrial compliance with federal and state environmental regulations and local sewer ordinances.

WES Source Control

In addition to the federal and state-mandated Industrial Pretreatment Program, our Industrial Permits Division also administers other programs. These other programs include:

  • Septage receiving
  • Extra-strength billing
  • Restaurant fats, oils and grease (FOG) reduction
  • Illicit discharge investigation
  • Surface water sampling
  • Temperature monitoring
  • Mercury minimization activities

Industrial Pretreatment

Fats, Oil and Grease

Septage Receiving

Contact Us
Department Staff
Chris Desiderati
Source Control Coordinator
503-557-2834
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Local Discharge Limits

PollutantLimit (expressed as a daily maximum in mg/L)
Arsenic0.16
Cadmium0.24
Chromium2.77
Copper3.38
Lead0.81
Mercury0.0035
Nickel2.45
Silver0.43
Zinc2.61
 
Cyanide, total1.20
Total Toxic Organics2.13
 
Oil and Grease (total)100
Oil and Grease (non-polar)100
Oil and Grease (polar)300
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Best Management Practices for Fats, Oils and Grease

Residual fats, oils and grease (FOG) are by-products that food service establishments must constantly manage. Typically, FOG enter a facility's plumbing system from dish washing, floor cleaning and equipment sanitation. Sanitary sewer systems are neither designed nor equipped to handle FOG that accumulates inside municipal sewer collection system pipes. Over 30% of sanitary sewer blockages are the result of pipe buildup from FOG in the sewer pipes. The best way to manage FOG is to keep the material out of the plumbing systems. The following are suggestions for proper FOG management.

Dry Clean-Up

Practice dry cleanup. Remove food waste with "dry" methods such as scraping, wiping or sweeping before using "wet" methods that use water. Wet methods typically wash the water and waste materials into the drains where it eventually collects on the interior walls of the drainage pipes. Do not pour grease, fats or oils from cooking down the drain and don't use sinks to dispose of food scraps. Likewise, it is important to educate kitchen staff not to remove drain screens as this may allow cups, straws and other utensils to enter the plumbing system during cleanup. The success of dry clean up is dependent upon the behavior of the employee and availability of the tools for removal of food waste before washing. To practice dry clean up:

  • Use rubber scrapers to remove fats, oils and grease from cookware, utensils, chafing dishes and serving ware.
  • Use food-grade paper to soak up oil and grease under fryer baskets.
  • Use paper towels to wipe down work areas. Cloth towels will accumulate grease that will eventually end up in your drains from towel washing/rinsing.

Spill Prevention

Preventing spills reduces the amounts of waste on food preparation and serving areas that will require clean up. A dry workplace is safer for employees in avoiding slip, trips and falls. For spill prevention:

  • Empty containers before they are full to avoid spills.
  • Use a cover to transport interceptor contents to rendering barrel.
  • Provide employees with the proper tools (ladles, ample containers, etc.) to transport materials without spilling.

Maintenance

Maintenance is key to avoiding FOG blockages. For whatever method or technology is used to collect, filter and store FOG, ensure that equipment is regularly maintained. All staff should be aware of, and trained to perform, correct cleaning procedures, particularly for under-sink grease traps that are prone to break down due to improper maintenance. A daily and weekly maintenance schedule is highly recommended.

  • Contract with a management company to professionally clean large hood filters. Small hoods can be hand-cleaned with spray detergents and wiped down with cloths for cleaning. Hood filters can be effectively cleaned by routinely spraying with hot water, with little or no detergents, over the mop sink  connected to a grease removal device. After hot water rinse (separately trapped), filter panels can go into the dishwasher. For hoods to operate properly in the removal of grease-laden vapors, the ventilation system will also need to be balanced with sufficient make-up air.
  • Skim/filter fryer grease daily and change oil when necessary. Use a test kit provided by your grocery distributor rather than simply a "guess" to determine when to change oil. This extends the life of both the fryer and the oil. Build-up of carbon deposits on the bottom of the fryer act as an insulator that forces the fryer to heat longer, thus causing the oil to break down sooner.
  • Collect fryer oil in an oil rendering tank or transport it to a bulk oil rendering tank instead of discharging it into a grease interceptor or waste drain.
  • Cleaning intervals depend upon the type of food establishment involved. Some facilities require monthly or bi-monthly cleaning. Establishments that operate a large number of fryers or handle a large amount of fried foods may need at least monthly cleanings. Full cleaning of grease traps (removing all liquids and solids and scraping the walls) is a worthwhile investment. Remember, sugars, starches and other organics accumulate from the bottom up. If sediment is allowed to accumulate in the trap, it will need to be pumped more frequently.
  • Develop a rotation system if multiple fryers are in use. Designate a single fryer for products that are particularly high in deposits, and change that one more often.

Oil and Grease Collection / Recycling and Food Donations

Fats, oils and grease is commodities that if handled properly can be treated as a valuable resource. Some rendering companies will offer services free-of-charge and others will give a rebate on the materials collected.

Use 25-gallon rendering barrels with covers for onsite collection of oil and grease other than from fryers. Educate kitchen staff on the importance of keeping outside barrels covered at all times. During storms, uncovered or partially covered barrels allow storm water to enter the barrel resulting in oil running onto the ground and possibly into storm drains and can "contaminate" an otherwise useful by-product.

  • Use a 3-compartment sink for ware washing. Begin with a hot pre-wash, then a scouring sink with detergent, then a rinse sink.
  • Make sure all drain screens are installed.
  • Prior to washing and rinsing, use a hot water ONLY (no detergent) prerinse that is separately trapped to remove non-emulsified oils and greases. Wash and rinse steps should also be trapped.
  • Empty grill-top scrap baskets or scrap boxes and hoods into the rendering barrel.
  • Easy does it! Instruct staff to be conservative about their use of fats, oils and grease in food preparation and serving. Ensure that edible food is not flushed down your drains. Edible food waste may be donated to a local food bank. A local garbage feeder who uses food discards for feeding livestock can collect inedible food waste. Food donation is a win-win situation. It helps restaurants reduce disposal costs and it puts the food in the hands of those who can use it.

Grease Traps

  • For grease traps to be effective, the units must be properly sized, constructed and installed in a location to provide an adequate retention time for settling and accumulation of FOG. If the units are too close to the FOG discharge and do not have enough volume, the emulsified oils will pass through the unit without being captured. For information on properly locating, constructing and sizing grease traps, contact your local county and city representatives and examine EPA guidance documents.
  • Ensure all grease-bearing drains discharge to the grease trap. These include mop sinks, wash sinks, prep sinks, utility sinks, pulpers, dishwashers, prerinse sinks, can washes and floor drains in food preparation areas such as those near a fryer or tilt/steam kettle. No toilet wastes should be plumbed to the grease trap.
  • If these suggested best management practices do not adequately reduce FOG levels, the operator may consider installing a second grease trap with flow-through venting. This system should help reduce grease effluent substantially.

Consumer Tip

Buyer beware! When choosing a method of managing your oil and grease, ensure that it does what the vendor says it will do. Some technologies or "miracle cures" don't eliminate the problem but result in grease accumulations further down the sewer line. "Out of sight" is not "out of mind." Check the vendor's references.

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