12.52.050 Preservation of the hydrologic cycle within the North Creek Protection Area (NCPA)

12.52.050 Preservation of the hydrologic cycle within the North Creek Protection Area (NCPA).

The North Creek Protection Area (NCPA) is assigned to properties within the Fitzgerald/35th Avenue SE Subarea as a special regulation to protect the known critical fish and wildlife habitat present in this subarea through special low impact development (LID) overlay regulations. The Palm, Woods and Cole Creek drainage basins within the Fitzgerald/35th Avenue SE Subarea have been identified as particularly important sources of cool water for North Creek, via groundwater and surface water movement. Cool water promotes the long-term vitality of the fisheries resources found in North Creek. This chapter augments and amends other development codes by establishing regulations for the maintenance and restoration of the hydrologic cycle, particularly as it affects protection of surface and groundwater resources. This land use section shall be used in conjunction with the latest version of the Bothell Surface Water Design Manual as contained within the Bothell Design and Construction Standards and Specifications (Bothell Standards).

A. Intent and Application. These standards are applied in addition to zoning and other code regulations. In the event of a conflict with another code regulation, the provision which provides the greater protection to the resource shall be applied. Authority is provided for the community development director and public works director to allow modification of the specific design and construction standards and regulations identified in this chapter to accommodate these provisions.

B. Exceptions. The special provisions of the NCPA shall not be applied to the following activities or developments; provided, however, that all activities and developments shall fully comply with the city’s critical areas regulations of Chapter 14.04 BMC, the Bothell Design and Construction Standards, including the Bothell Surface Water Design Manual, the tree retention requirements of Chapter 12.18 BMC and all other applicable city-wide regulations:

1. Existing development on lots of record in existence on or before March 15, 2008;

2. Construction of one single-family residence on any lot of record legally established on or before March 15, 2008;

3. Short subdivisions within lands zoned R 9,600 (LID) and R 40,000 (LID) proposing a lot area of 40,000 square feet or greater may be exempt from the special provisions of this section provided the short subdivision:

a. Creates no more than four lots; and

b. Complies with the area, dimensional, setback, building coverage, hard surface coverage, building height and other standards of the city’s R 40,000 zoning classification as stipulated within Chapter 12.14 BMC; and

c. Complies with all other city-wide regulations including the critical areas regulations, the tree retention requirements of Chapter 12.18 BMC, other applicable provisions of the zoning code, the latest edition of the Bothell Surface Water Design Manual and other city-wide standards; and

d. The maximum lot area provisions of BMC 12.14.030(B)(2)(c) shall not apply to such short subdivisions, however the provisions of BMC 12.14.030(B)(2)(c)(1) through (4) shall apply.

a. The proposed activity will not adversely affect the infiltration and recharging of the groundwater table in a manner that will result in decreases in groundwater interflow to surface water.

b. Site design and storm water facilities shall be designed in accordance with these low impact development regulations as provided herein and the 2016 Bothell Surface Water Design Manual.

2. Effective Impervious Surface Coverage. Within the NCPA, the goal is to have no net increase in undetained and untreated effective impervious area (EIA) through the application of these requirements and the Bothell Surface Water Design Manual.

a. Effective impervious area (EIA) shall not exceed 20 percent for lands zoned R 9,600 (LID) and R 40,000 (LID). EIA shall be based upon the gross area of the total site.

b. The effective impervious area standard shall not apply to existing development, lots of record in existence on or before March 15, 2008, and other development activities as identified in subsection B of this section.

a. Within lands zoned R 9,600 (LID) and R 40,000 (LID), an area equal to 60 percent of the gross site area shall be preserved as permanent forest cover. Areas allowed to be credited as forest cover include:

(1) Those portions of the site that contain intact forest lands as defined within this chapter; or

(2) Intact forest areas within critical areas and critical area buffers as defined by Chapter 14.04 BMC; provided, however, that lands within a critical area or a critical area buffer shall retain 100 percent of any intact forest and vegetation; or

(3) Forest rehabilitation or forest restoration lands subject to the following:

(A) Forest rehabilitation is preferred over forest restoration. Forest rehabilitation occurs on lands which contain existing stands of mature (50 or more years old) trees with or without a middle layer of plants (understory plants), where soil types are capable of infiltration or are suitable for dispersion of project surface water through gravity systems, and shall be consistent with the following:

(1) A forest rehabilitation or restoration plan prepared by a qualified expert in forestry, forest rehabilitation or restoration, landscape architecture or another field familiar with forest rehabilitation within which the expert shall make specific recommendations regarding the type of plant materials, the number of plants to be installed, any soil amendments that are needed to rehabilitate the forest, a maintenance and management plan consistent with subsection (C)(3)(d) of this section and a contingency plan to be implemented should the forest rehabilitation not meet its objectives;

(2) The forest rehabilitation plan shall be fully implemented or bonded prior to the issuance of any final occupancy permits for the subject property; or

(B) Forest restoration occurs on lands where the native trees have been removed and/or replaced for agricultural or ornamental purposes but the native soils remain in place and shall be consistent with the following:

(1) A forest restoration plan prepared by a qualified expert in forestry, forest rehabilitation or restoration, landscape architecture or another field familiar with forest restoration within which the expert shall make specific recommendations regarding the type of plant materials, the number of plants to be installed, identify soil amendments needed to restore the forest, a maintenance and management plan consistent with subsection (C)(3)(d) of this section and shall include a contingency plan to be implemented should the forest rehabilitation not meet its performance objectives; and

(2) The forest restoration plan shall be implemented or bonded prior to the issuance of any final occupancy permits for the subject property.

(C) Lands used for low impact development storm water facilities that have a high potential for functioning as a forest in terms of protecting the hydrological cycle and other habitat benefits consistent with forest rehabilitation or restoration including planting with predominantly woody vegetation and that the LID facility is part of a bioretention and/or dispersion system as outlined within the Bothell Surface Water Manual.

b. A bond equal to 120 percent of the cost of installing the forest rehabilitation or restoration plan shall be submitted to the city pursuant to BMC 12.18.170 if the applicant proposes to request occupancy of the development prior to completion of the plan.

c. Improvements allowed within forest areas are limited to:

(1) Surface water dispersion systems as described in the Bothell Surface Water Design Manual;

(2) Recreational trails not exceeding three feet in width and not requiring more than 18 inches of cut or fill and shall be constructed of a pervious surface consisting of wood chips, native soils, or similar materials.

d. All preserved, rehabilitated, or restored forest areas must be accompanied by a management plan addressing:

(1) Ownership of the forest area, which may include:

(A) Private ownership and management for forest area on individual lots or parcels that are not of sufficient size and character to allow effective management by the city or other public entity. Any such forest area shall be preserved within a recorded separate tract with a plat restriction that provides:

(1) An assurance that native vegetation will be preserved or restored to meet the criteria of this chapter; and

(2) The right of the city to enforce the terms of the restriction.

(B) Private ownership by an individual lot owner, undivided interest by each owner of a building lot within the development with the ownership interest passing with the ownership of the lot, or held by an incorporated homeowners’ association within a separate tract with a plat condition providing for management by a public entity when the city determines that:

(1) The forest area is of sufficient size and character to allow effective management by the city or other public entity; or

(2) The forest area contains critical areas that are best managed by a public entity in conformance with criteria in BMC 14.04.290.

(C) Dedication of a separate tract containing the forest area to a public agency, or conveyance to a legal entity such as an incorporated land trust, which ensures the ownership, protection and maintenance, and protection of the forest cover.

(2) A management plan for the forest cover area shall include:

(A) Marking of the boundaries of the area, which includes open rail fencing to provide for ready field identification and prevent encroachment upon the area and signage which shall describe the purpose of the forest area and identify ownership and which shall be placed no more than 100 feet apart around the entire forest area boundary;

(B) Provisions for installation and monitoring of any required rehabilitation or restoration plantings, including monitoring of the survival of plantings for a five-year or longer period where dead or dying plants shall be replaced as needed;

(D) Management of any storm water management facilities allowed within the forest area.

4. Site Design Regulations. Site design shall consider the information gathered in the special site study to identify and describe the natural processes existing on and around the development site and how the site design, layout and arrangement of the site improvements preserve natural processes to the maximum extent feasible.

a. Vehicle and pedestrian circulation systems shall be designed to minimize alteration of topography and natural hydrologic features and processes through:

(1) Roads, walkways and parking areas shall be designed to follow natural contours, avoid changes to the existing flow patterns of surface water, and maintain consolidated areas of natural topography and vegetation. Vehicle access shall be located in the least sensitive area of the site to the maximum extent feasible;

(2) Road location and circulation patterns shall reduce or eliminate stream crossings and encroachment on critical areas and their buffers or, if impacts occur, any impacts are mitigated consistent with Chapter 14.04 BMC;

(3) Graded slopes and alteration of vegetation cover shall be avoided by road placement, and through use of retaining walls, which allow the maintenance of existing natural slope areas and shall be preferred over graded artificial slopes;

(4) Utilities shall be located within roadway and driveway corridors and rights-of-way to the maximum extent feasible to avoid additional clearing for multiple corridors.

b. Layout of lots or structures shall:

(1) Avoid portions of the site that provide for important hydrologic and critical area functions;

(2) Minimize access roadway or driveway length and area and use common access drives.

c. Design of structures and improvements shall minimize alteration of existing topography, minimize disturbance to soils and native vegetation, and provide for water infiltration and interflow consistent with these regulations and the Bothell Surface Water Design Manual.

(1) Excavation shall be prohibited from intruding into that part of the groundwater table which experiences saturated soil conditions, as measured during the dry season.

(2) Building location and design shall allow the maintenance of existing topography through:

(A) Use of pole or pin-type construction which conforms to the existing topography is preferred.

(B) Structures shall be tiered to conform to existing topography and to minimize topographic modification.

(C) Use of foundation walls as retaining walls is preferable to rock or concrete walls built separately and away from the building. Freestanding retaining devices are only permitted when they cannot be designed as structural elements of the building foundation.

(D) Standard prepared building pads (slab on grade) resulting in grading more than five feet outside the building footprint area or more than five feet of topographic modification are prohibited.

(3) Retaining walls and exposed foundations more than three feet in height shall be screened by vegetation.

1. To accommodate low impact development, the community development director is authorized to modify Chapters 12.14, 12.18, and 12.20 BMC, as specifically described below, without the need for a variance as provided for in Chapter 12.36 BMC. The city of Bothell shall decline to approve modifications in cases where conflicts occur with Imagine Bothell... Comprehensive Plan and Fitzgerald/35th Avenue SE Subarea plan policies or if the public health, safety and welfare would not be furthered by the proposed modification.

a. BMC 12.14.030(A) may be modified pursuant to the following:

(1) Within the R 40,000 (LID) zoning classification, the minimum lot area may be reduced by as much as 60 percent, and within the R 9,600 (LID) zoning classification, the minimum lot area may be reduced by as much as 50 percent. For example, properties with a zoning classification of R 40,000 may have a minimum lot area of 16,000 square feet and properties with a zoning classification of R 9,600 (LID) may have a minimum lot area of 4,800 square feet.

(2) Within the R 40,000 (LID) zoning classification, the minimum lot circle may be reduced by as much as 60 percent, and within the R 9,600 (LID) zoning classifications, minimum lot circle diameter may be reduced by as much as 50 percent. For example, properties with a zoning classification of R 9,600 (LID) may have a minimum lot circle diameter of 40 feet.

(3) Lots which are modified under subsections (D)(1)(a)(1) and (2) of this section shall provide for a special setback of 25 feet along common property lines whenever such lots are located within 50 feet of an existing primary single-family building.

b. Parking lot landscaping location and dimensional requirements in BMC 12.18.090 may be modified by the community development director to consolidate parking lot landscaping areas to allow landscape areas to function as dispersion or bioretention facilities. The required perimeter landscaping and the amount of internal parking lot landscaping shall not be varied by this provision.

c. In addition to the circumstances within BMC 12.18.160 where the community development director may grant modification to the required landscape standards of Chapter 12.18 BMC, the community development director may also grant modification to accommodate dispersion and bioretention facilities within required landscape areas. All landscape areas shall be graded to provide for water retention where feasible. Except as accessory to single-family dwellings, turf shall be discouraged and limited to recreation or community gathering areas. (Ord. 2215 § 3 (Exh. B3), 2016; Ord. 2200 § 2 (Exh. B), 2016; Res. 1332; Ord. 2163 § 2 (Exh. B-3), 2014; Ord. 2053 § 3 (Exh. C), 2010; Ord. 1988 § 1, 2008. Formerly 12.52.040).