Chapter 17A.40
STORMWATER DRAINAGE

Sections:

17A.40.010    Off-Site Mitigation.

17A.40.020    Pre-Existing Stormwater Facilities.

17A.40.030    Acceptance of Pre-Existing Stormwater Facilities.

17A.40.070    County Regional Drainage Facilities.

17A.40.080    Discharge to Privately Owned Property.

17A.40.090    Discharge to Publicly Owned Regional Retention and/or Detention Facilities.

17A.40.100    Privately Constructed Regional Retention and/or Detention (R/D) Facilities.

17A.40.010 Off-Site Mitigation.

The County recognizes that application of the design standards set forth in the Manual does not always fully prevent any impacts downstream and in these extreme cases, the applicant may be required to provide off-site mitigation as determined by the County. (Ord. 2008-59s § 2 (part), 2008; Ord. 99-24S § 2 (part), 1999)

17A.40.020 Pre-Existing Stormwater Facilities.

The applicant/person required to construct a stormwater facility pursuant to older or replaced site development or stormwater drainage Regulations, which is covered by a maintenance or defect financial guarantee or which has been released from all required financial guarantees prior to the effective date of this Title, and all persons holding title to the property for which a facility was required shall be responsible for the continual operation and maintenance of the facility in accordance with standards and requirements that were the basis of approval of the site development permit and for any liability as a result of breach of these duties. (Ord. 99-24S § 2 (part), 1999)

17A.40.030 Acceptance of Pre-Existing Stormwater Facilities.

A.    The County may assume maintenance of pre-existing facilities only after the following conditions have been met:

1.    All necessary easements or dedications entitling the County to properly maintain the stormwater facility have been conveyed to the County;

2.    The Director of Planning and Public Works has determined maintenance of the facility will contribute to protecting or improving the health, safety, and welfare of the community based upon review of the following factors:

a.    Existence of or potential for flooding,

b.    Existence of or potential for downstream erosion,

c.    Existence of or potential for property damage due to improper function of the facility,

d.    Existence of or potential for safety hazard associated with the facility,

e.    Existence of or potential for degradation of surface or groundwater quality or in-stream resources,

f.    Existence of or potential for degradation to the general welfare of the community,

g.    Improvements in residential plats/PDDs have been completed on at least 80 percent of the lots,

h.    An inspection by the Director has determined that the stormwater facilities are functioning as designed,

i.    The stormwater facilities have had at least two years of satisfactory operation and maintenance, unless otherwise waived by the Director,

j.    The person or persons holding title to the properties served by the stormwater facilities submit a petition containing the signatures of the title holders of more than 50 percent of the lots served by the stormwater facilities requesting that the County maintain the stormwater facilities,

k.    All easements and/or dedicated tracts required under this Chapter, entitling the County to properly operate and maintain the subject stormwater facilities, have been conveyed to Pierce County and have been recorded with the Pierce County Auditor,

l.    The person or persons holding title to the properties served by the stormwater facilities show proof of the correction of any defects in the drainage facilities, as required by the Director;

3.    The Director of Planning and Public Works has declared in writing acceptance of maintenance responsibility by the County. Copies of this document will be kept on file in the Pierce County Planning and Public Works record center and the Planning and Public Works Road Maintenance main office.

B.    A stormwater facility which does not meet the criteria of this Section shall remain the responsibility of the applicant/person required to construct the facility and persons holding title to the property for which the facility was required. The decision of the Director is final and is not appealable.

(Ord. 2017-12s § 2 (part), 2017; Ord. 2015-48s § 1 (part), 2015; Ord. 2015-25s § 2 (part), 2015; Ord. 99-24S § 2 (part), 1999)

17A.40.070 County Regional Drainage Facilities.

A.    Due to the nature of County regional drainage facilities to control surface water runoff from large tracts of land, it is recognized that it may not be feasible, both fiscally and physically, to control runoff as stipulated in the Manual for new or retrofit facilities. The County shall make every effort reasonable to control runoff to the discharge, storage, and quality criteria established in the Manual. Where determined impractical by the Director of Planning and Public Works, the County will be allowed to modify the criteria for regional facilities and design for maximization of the available land space for control of stormwater. In this case, the County shall design the facility for the primary function of stormwater control and any other multi-use functions shall be considered only after maximizing the stormwater aspects of the facility. Facilities that do not meet the Manual's Volume I minimum requirements will not accept excess discharge flows from new developments.

B.    Drainage facilities constructed by private development to mitigate for the impacts of new development or re-development will not be viewed as regional drainage facilities and shall meet all provisions of this Title.

(Ord. 2017-12s § 2 (part), 2017; Ord. 2015-48s § 1 (part), 2015; Ord. 2015-25s § 2 (part), 2015; Ord. 2008-59s § 2 (part), 2008; Ord. 99-24S § 2 (part), 1999)

17A.40.080 Discharge to Privately Owned Property.

If the project site discharges to a privately owned closed depression, the applicant must obtain written permission/easements from the owner(s) of record for both the closed depression and potential overflow routes receiving the runoff. The applicant shall record the information with the Pierce County Auditor. This information shall be recorded with all affected property titles including those for the depression, overflow route, and the applicant's property. If easements cannot be obtained, discharge to the pothole may be allowed on a case by case basis to match the predeveloped rates, increase the pond size and meet additional protective criteria described in Volume III of the Manual. (Ord. 2008-59s § 2 (part), 2008; Ord. 99-24S § 2 (part), 1999)

17A.40.090 Discharge to Publicly Owned Regional Retention and/or Detention (R/D) Facilities.

As determined by the County on a site-by-site basis, the developer shall have the option of paying to the County the anticipated costs for designing and constructing an on-site stormwater retention/detention facility including land costs as required above in-lieu-of constructing such a facility. The Manual describes the standards and conditions of this option in Volume III. (Ord. 2008-59s § 2 (part), 2008; Ord. 99-24S § 2 (part), 1999)

17A.40.100 Privately Constructed Regional Retention and/or Detention (R/D) Facilities.

In lieu of individual systems, applicants may design and build regional facilities in accordance with the design requirements of Category A or B set forth in Volume III of the Manual, as applicable and with excess capacity which, when completed, may be dedicated to the County. Such a facility may be on-site or off-site. Upon County approval of the facility, the County may:

A.    Accept the dedicated facility; and

B.    If funds are available as determined by the Director of Pierce County Planning and Public Works and the facility is constructed in a location within a basin studied by Pierce County Surface Water Management and is currently budgeted for in the approved six-year capital facilities plan, reimburse the developer for the excess capacity provided by the facility at a rate mutually agreed upon; or

C.    Enter into a latecomers agreement with the developer for reimbursement as other properties are developed which opt to discharge to the regional facility.

(Ord. 2017-12s § 2 (part), 2017; Ord. 2015-48s § 1 (part), 2015; Ord. 2015-25s § 2 (part), 2015; Ord. 2008-59s § 2 (part), 2008; Ord. 99-24S § 2 (part), 1999)