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1. What is a levee?

About

A levee is a man-made structure designed and constructed to contain, control or divert water to prevent flooding. CDID#1’s levees are primarily made of material dredged from the Cowlitz and Columbia Rivers. The Columbia River levee consists of coarse river sand to silt and clay. Part of the Cowlitz River levee was constructed of impervious clay and the remainder was constructed of a gravel cap over silt, sand, clay, gravel and occasional cobble. The levees are built at an elevation to match the Columbia River 1884 flood elevation plus 5-feet of freeboard. Most of our levees are built on easements, which means that anyone wanting to do work within the levee right-of-way must apply for a permit.

Area

The federal portion of our levee system was built by the USACE. It begins at the Cowlitz River north of Fishers Lane in Kelso, extends to and along the Columbia River to Willow Grove Road, continues along backwaters to the Coal Creek Slough and terminates at our Main Pump Station on Pacific Way in Longview.

A separate interior levee extends westerly along Pacific Way in Longview from 30th Avenue to our Main Pump Station. This non-federal levee intercepts runoff from hill side areas above Longview so the water can be collected and pumped out to the Columbia River.

2. Is the levee accredited?

About

Yes. In 2014, the U.S. Army Corps of Engineers (USACE) published a report concluding that CDID# 1’s levee system can be reasonably expected to protect against the 1% annual chance exceedance flood (also referred to as the 100-year flood). Their report was a pre-requisite for levee accreditation from the Federal Emergency Management Agency (FEMA) and eligibility for participation in the National Flood Insurance Program (NFIP). 

CDID# 1’s NFIP levee system evaluation will expire on July 31, 2024.

CDID# 1 also participates in two programs administered by the USACE to ensure we maintain our levee system in conformance with federal standards.

Inspections

• Rehabilitation and Inspection Program, Engineer Regulation (ER) 500-1-1:
  A routine annual inspection which takes about one day to complete. It involves driving the levee system to evaluate whether the flood control works will provide the intended degree of protection, and assess whether our maintenance program is adequate.
• Periodic Inspection, National Levee Safety Program Act of 2007:
  A thorough review of all CDID# 1 levees and stormwater facilities conducted every five years. The inspection is conducted entirely on foot, takes approximately four days to complete, and consists of a large multi-disciplinary team of engineers.

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1. How do I borrow a gate key?

Contact our main office at 360-423-2493 or email CDID #1. Someone will make arrangements to meet and open the gate for you or can sign a gate key use agreement to check out a key. Keys shall not be duplicated.

2. How should I dispose of grass clippings?

Mulch grass clippings and leave them on your lawn after mowing, or bag grass clippings and put them in the garbage. Do not throw grass clippings into the ditch or over the bank. Do not blow grass clippings or leaves into the street or storm drain.

3. What can I do about mosquitoes?

The Cowlitz County Mosquito Control District works from March through October to control mosquitoes in Cowlitz County. Any resident of Cowlitz County can contact the Mosquito Control District to request help with mosquito problems. There is no charge for this service, they are funded by an assessment on all property within the County. 

For help, call the Mosquito Hotline at 360-425-5658 or their main office at 360-423-5311.

4. How do I find out where my property lines are?

The City of Longview and Cowlitz County both provide Geographic Information System (GIS) maps to the general public. Areas depicted are approximate, and not necessarily accurate to surveying or engineering standards but are useful for illustration purposes.

Resources

• City of Longview GIS Department
• Cowlitz County GIS Department
• Cowlitz County online GIS maps

5. How do I find out about bidding opportunities?

CDID #1 is a special purpose district pursuant to Chapter 85.15 of the Revised Code of Washington (RCW). Special districts are exempt from competitive bidding (RCW 39.04) and prevailing wage requirements (RCW 39.12) but we solicit quotes for projects over $10,000 and bids for contracted improvements over $200,000. Bid opportunities are publicly advertised with a Call for Bids in the local newspaper.

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1. What is a nutria?

Nutria is a medium sized semi-aquatic rodent native to South America. A nutria can grow up to 40 inches from its nose to the tip of its rat-like tail. It weighs an average of 12 pounds, although some may reach up to 40 pounds. It is an herbivore and varies in color from dark brown to yellowish brown and occasionally white.

2. How did they get here?

Nutria were introduced into Washington for the fur-farming industry in the 1930’s. By 1943, there were feral populations. The nutria is a prolific breeder, capable of producing two litters a year. Populations are spreading rapidly throughout Washington.

3. When are nutria most active?

Nutria are active year-round. Although they can be seen at any time, they are most active at twilight and throughout the night. They may be seen feeding during the day when food is scarce, or basking in the sun when temperatures are low.

4. Are they destructive or dangerous?

A nutria consumes 25% of its body weight each day. Because it eats roots and stems, it can destroy ten times more plant matter than it eats. Nutria are known to destroy wetlands and marshes, and turn shoreline areas into muddy bogs. They host a variety of parasites and pathogens and, when cornered or captured, nutria are aggressive and can inflict serious injury to people and pets.

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1. How much does it cost to buy regional detention?

The current purchase price for regional detention capacity is $3.19 per cubic foot of stormwater runoff. It is a one-time non-refundable fee.

2. What detention volume is required?

The required detention volume is based on the different in runoff volume generated during the pre-developed and post-developed condition for the 100 year, 24 hour event. Participants wanting to purchase regional detention capacity should submit a stormwater report, signed and dated by an engineer licensed in Washington state, or other licensed professionals if appropriate.

3. Is everyone eligible to buy regional detention?

The option to buy regional detention capacity is available to anyone. However, in order to be eligible, your project must be located such that discharge from your site will reach CDID #1’s Regional Detention Basin using existing conveyances. Primary and most secondary ditches with unrestricted flow are available for direct discharge. Some of our secondary ditches may have to be improved or hydraulically modeled to demonstrate sufficient flow in order to be considered eligible. Discharges to small ditches and finger drains are not eligible for regional detention. The participant is responsible for the cost of any additional analysis or improvements required to determine eligibility, if needed.

4. How much capacity is available?

CDID #1’s Regional Detention Basin was constructed with an original storage capacity of 480,000 cubic feet of volume. As of January 2020, approximately 200,000 cubic feet of remaining storage volume is available to purchase.

5. What rainfall rate do I use?

Design storm data is defined by of the City of Longview Stormwater Manual for the Longview-Kelso urbanized area (see Appendix C).  Rainfall intensity for the 100-year storm is 0.26 inches per hour, and the total rainfall depth for the 100-year, 24-hour event is 6.17".

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1. Are the CDID #1 ditches waters of the U.S.?

Yes. CDID #1’s ditches are considered Waters of the U.S. and subject to the Clean Water Act.

Discharges to our ditches must meet City of Longview or Cowlitz County stormwater requirements, and comply with the 2019 Stormwater Management Manual for Western Washington. 

Permitted Discharges

Discharges from our ditches to surface waters are permitted as a Municipal Separate Storm Sewer System (MS4) under the Western Washington Phase II Municipal Stormwater National Pollutant Discharge Elimination System (NPDES) permit. As a Phase II Secondary Permittee, CDID #1 is required to also adopt and implement its own Stormwater Management Program (PDF) to control stormwater flows, educate the public, eliminate illicit discharges and reduce contaminated runoff.

2. What is an illicit discharge?

An illicit discharge is any discharge to a municipal separate storm sewer (MS4) that is not comprised entirely of stormwater or of authorized non-stormwater discharges permitted under an NPDES permit.  Some non-stormwater discharges may be allowable, such as flows from fire fighting activities and air conditioning condensate.  Outdoor washing acitivites that flow to a storm drain inlet may be considered an illicit discharge if the water becomes contaminated with roadway pollutants as it flows across driveways and along curb/gutter.  

3. Are non-stormwater discharges allowed?

Illicit discharges including most non-stormwater flows, illegal dumping, or improper disposal of hazardous materials, pet waste, yard debris and litter are strictly prohibited in CDID #1 ditches. Only certain non-stormwater flows are allowed including:

• Air conditioning condensation
• Discharges covered by another National Pollutant Discharge Elimination System (NPDES) permit
• Diverted stream flows
• Emergency firefighting water
• Flows from riparian habitats and wetlands
• Footing drains
• Foundation drains
• Irrigation water from agricultural sources
• Rising groundwater, or uncontaminated groundwater (pumped or infiltrated)
• Springs
• Water from crawl space sumps

4. Can I drain my swimming pool or hot tub to the ditch?

Only if you contact us in advance to authorize it! Swimming pool and hot tub water must be dechlorinated to a concentration of 0.1 parts per million, pH adjusted and possibly re-oxygenated before being discharged. Discharge volume and flow must be controlled to prevent erosion and the re-suspension of sediment in the ditch. Pool and hot tub cleaning wastewater and filter backwash may not be disposed of in the ditch.

Other Prohibited Discharges

Other potable water discharges are also prohibited, such as from:

• Dust control waters
• Fire hydrant flushing
• Irrigation runoff
• Lawn watering
• Washdown waters
• Water line flushing

5. What do I need to know before starting construction?

CDID #1 is required to implement and enforce a Stormwater Management Program (PDF) to reduce pollutants in stormwater runoff to our ditches from new development, re-development and construction site activities. The program applies to both private and public improvements, including roads, and is consistent with stormwater regulations adopted by the City of Longview, City of Kelso and Cowlitz County. CDID #1 coordinates with these local jurisdictions to permit and manage projects within our system boundary.

Notify Us

If you already have a CDID #1 encroachment permit and are ready to start work, notify us at least 48 hours in advance. Depending on the project, CDID #1 may inspect the site to ensure appropriate temporary erosion and sediment controls are in place, and/or request a pre-construction meeting with you or your contractor.

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1. Will I be notified before aquatic herbicides are applied?

CDID #1 will notify all water front residences and businesses within ¼ mile in each direction along and across the ditch being treated by mail or door hangar. The notification will identify the name and location of the ditch to be treated, treatment date(s), product to be used, active ingredient and the plants being targeted.

CDID #1 will also post signs describing any water use restrictions or advisories in the treated and potentially affected areas no more than 48 hours prior to treatment.

2. Which ditches are treated with aquatic herbicide?

• Ditch 5
• Ditch 6 West
• Ditch 10
• Ditch 14

For more information, view the Aquatic Herbicide Application Map (PDF)