WAC 222-24-040   Water crossing structures.  *(1) General provisions for all typed waters.

     In addition to the applicable general provisions below, installation, maintenance and removal of water crossing structures in or across the bankfull width of Type S or F Waters are subject to hydraulic code rules, chapter 220-110 WAC, and require hydraulic project approval (HPA) issued by the department of fish and wildlife. HPAs may be required on Type Ns and Np Waters.

     (a) Bridges are required for new crossings and reconstructed crossings of any typed waters regularly used for recreational boating.

     (b) Structures containing concrete must be sufficiently cured prior to contact with water.

     (c) One end of each new or reconstructed permanent log or wood bridge shall be tied or firmly anchored if any of the bridge structure is within 10 vertical feet of the 100-year flood level.

     (d) Alterations or disturbance of the stream bed, bank or bank vegetation must be limited to that necessary to construct the project. All disturbed areas must be stabilized and restored according to the recommended schedule and procedures found in section 3 of the board manual. This requirement may be modified or waived by the department, in consultation with the department of fish and wildlife, if precluded by engineering or safety factors.

     (e) When earthen materials are used for bridge surfacing, only clean sorted gravel may be used, a geotextile lining must be installed and curbs of sufficient size shall be installed to a height above the surface material to prevent surface material from falling into the stream bed.

     (f) Wood removed from the upstream end of culverts and bridges will be placed at the downstream end of such culverts and bridges in such a way as to minimize obstruction of fish passage and to the extent practical while avoiding significant disturbance of sediment, in connection with maintenance activities.

     *(2) Bridges over Type Np and Ns Waters. In addition to the applicable general provisions above, installation, maintenance, and removal of permanent bridges in or across Type Np and Ns Waters are subject to the following:

     (a) Permanent bridges must not constrict clearly defined channels and must be designed and installed to pass the 100-year flood. The bridge and its associated embankments and fills must provide sufficient erosion protection to withstand a 100-year flood event.

     (b) Excavation for and placement of the bridge foundation and superstructure must be located and conducted from outside the outer edge of the bankfull width. This requirement may be waived by the department, in consultation with the department of fish and wildlife, if it can be demonstrated that these activities may be conducted in such a manner to prevent damage to public resources.

     (c) Earthen embankments constructed for use as bridge approaches must be provided with sufficient erosion protection to withstand a 100-year flood event.

     *(3) Culvert installation for Type Np and Ns Waters. In addition to applicable general provisions above, installation, maintenance and removal of permanent culverts in or across Type Np and Ns Waters are subject to the following provisions:

     (a) All permanent culverts must be designed to pass the 100-year flood event with consideration for the passage of debris likely to be encountered.

     (b) The culvert and its associated embankments and fills must have sufficient erosion protection to withstand the 100-year flood event. Erosion protection may include armored overflows or the use of clean coarse fill material.

     (c) If the department determines that because of unstable slopes the culvert size shown in the board manual, section 3, "Determining Culvert Size, Method A" would be inadequate to protect public resources, it may require a larger culvert designed using generally accepted engineering principles that meet the standards in (a) and (b) of this subsection.

     (d) No permanent culverts shall be installed that are smaller than:

     (i) 24 inches for Type Np Waters.

     (ii) 18 inches for Type Ns Waters in western Washington.

     (iii) 15 inches for Type Ns Waters in eastern Washington.

     (e) The alignment and slope of the culvert shall parallel the natural flow of the stream whenever possible.

     (f) Culverts must be designed and installed so they will not cause scouring of the stream bed and erosion of the banks in the vicinity of the project.

     (g) When the department determines that installing a culvert in a flowing stream will result in excessive siltation and turbidity, and siltation and turbidity would be reduced if stream flow were diverted, the department shall require the stream flow be diverted using a bypass flume or culvert, or by pumping the stream flow around the work area. This may include culvert installations that are within 0.25 miles of a Type S or F Water or within two miles of a hatchery intake in consultation with the department of fish and wildlife.

     (h) Fill associated with culvert installation must have sufficient erosion protection to withstand the 100-year flood.

     (i) Stream beds shall be cleared for a distance of 50 feet upstream from the culvert inlet of such slash or debris that reasonably may be expected to plug the culvert.

     (j) The entrance of all culverts shall have adequate catch basins and headwalls to minimize the possibility of erosion or fill failure.

     *(4) Temporary water crossings in Type Np and Ns Waters. In addition to the applicable general provisions above, installation, maintenance and removal of temporary bridges or other structures in or across Type Np and Ns Waters are subject to the following:

     (a) A temporary water crossing is intended for use during the life of an approved application/notification.

     (b) It must be constructed to facilitate abandonment when the intended use is complete or upon seasonal shutdown, whichever is sooner.

     (c) Temporary water crossings must be identified on the forest practices application or notification, along with an abandonment date.

     (d) Temporary water crossings may be used:

     (i) In western Washington if installed after June 1 and removed by September 30 of the same year.

     (ii) In eastern Washington if installed after the spring runoff and removed prior to October 15th.

     (iii) At other times, when the department and applicant can agree to specific dates of installation and removal and the extended dates result in equivalent levels of resource protection.

     (e) Temporary water crossings must be designed to pass the highest peak flow event expected to occur during the length of its intended use.

     (f) When the department determines that installing a culvert in a flowing stream will result in excessive siltation and turbidity, and siltation and turbidity would be reduced if stream flow were diverted, the department shall require the stream flow be diverted using a bypass flume or culvert, or by pumping the stream flow around the work area. This may include culvert installations that are within 0.25 miles of a Type S or F Water or within two miles of a hatchery intake, in consultation with the department of fish and wildlife.

     (g) Temporary water crossings shall be promptly removed and abandoned to the specifications approved by the department upon completion of use or by the date specified in the approved forest practices application, whichever is earlier. Approaches to the crossing shall be water barred and stabilized at the time of the crossing removal. The department may waive removal of the water crossing if the applicant secures an amended forest practices application, and the structure and its approaches meet all of the requirements of a permanent water crossing structure.

     (h) Temporary wetland crossings shall be abandoned and restored based on a written plan approved by the department prior to construction.

     (i) Temporary water crossings must be designed to provide the same level of protection for public resources as provided by rules during the length of its use.

     *(5) Properly prepared and maintained fords may be used in Type Np and Ns Waters during periods of low water.

     (a) Entry and exit points for each ford must be located as close to perpendicular along the stream as possible, but will not exceed 100 feet upstream or downstream of each other. Approaches to the ford will not run adjacent to the stream.

     (b) Ford locations must be shown on the forest practices application.

     (c) Best management practices for construction, maintenance and use will be utilized as appropriate or as required by conditions on the approved forest practices application.



[Statutory Authority: Chapter 34.05 RCW, RCW 76.09.040,[76.09.]050 , [76.09.]370, 76.13.120(9). 01-12-042, § 222-24-040, filed 5/30/01, effective 7/1/01. Statutory Authority: RCW 76.09.040 and chapter 34.05 RCW. 97-24-091, § 222-24-040, filed 12/3/97, effective 1/3/98. Statutory Authority: RCW 76.09.040, 76.09.170 and chapter 34.05 RCW. 94-01-134, § 222-24-040, filed 12/20/93, effective 1/1/94. Statutory Authority: RCW 76.09.060, 76.09.040 and chapter 34.05 RCW. 92-23-056, § 222-24-040, filed 11/17/92, effective 12/18/92. Statutory Authority: RCW 76.09.040, 76.09.050 and chapter 34.05 RCW. 92-15-011, § 222-24-040, filed 7/2/92, effective 8/2/92. Statutory Authority: RCW 76.09.040. 87-23-036 (Order 535), § 222-24-040, filed 11/16/87, effective 1/1/88. Statutory Authority: RCW 76.09.040 and 76.09.050. 82-16-077 (Resolution No. 82-1), § 222-24-040, filed 8/3/82, effective 10/1/82; Order 263, § 222-24-040, filed 6/16/76.]