The following policies and standards shall apply to any development, construction, or use carried out within a designated hydrologically related critical area:
(1) The Ordinary High Water Mark of a stream or lake, the edge of a wetland, and the outside edges of stream and/or wetland buffers shall be marked on the ground before any development, construction, or use is initiated.
(2) Any disturbance to existing riparian vegetation and any unique or sensitive vegetative species identified on the project site within the stream corridor shall be mitigated according to the standards set forth in Section
16C.03.10.
(3) Any disturbance to nesting areas and other sensitive wildlife habitat identified within a stream corridor shall be mitigated according to the standards set forth in Section
16C.03.10.
(4) Projects within the stream corridor shall be scheduled to occur at times and during seasons having the least impact to spawning, nesting, or other sensitive wildlife activities. Scheduling recommendations from the appropriate state and/or federal agency may be considered.
(5) Stormwater and Erosion Control. Developments that obtain a stormwater permit approved by a local, state or federal agency, and transportation projects using stormwater manuals that are deemed equivalent to the Yakima Regional Stormwater Manual are considered to have met the following required development standards that apply to all projects:
(a) Excavation, grading, cut/fills, compaction, and other modifications which contribute to erosion of upland soils shall be confined to the minimum necessary to complete the authorized work and avoid increased sediment load.
(b) The removal of ground-cover vegetation, excavation, and grading shall be scheduled for periods when soils are the least vulnerable to erosion, compaction and movement unless suitable protective measures are used to prevent erosion.
(c) The removal of ground-cover vegetation, excavation, and grading shall be scheduled to ensure the minimal duration of exposed, unprotected soils.
(d) Increases in impervious surface area, compaction of soil, changes in topography, and other modifications of land within a stream corridor which are determined will permanently increase stormwater and meltwater runoff into stream channels, drainage ways, and conduits, shall provide on-site or off-site facilities for the detention, control, and filtration of such increases.
(e) The discharge point for controlled stormwater and meltwater runoff and other outfall shall be designed and constructed to avoid causing erosion through the use of native riparian vegetation where possible or by reducing velocity, use of rock spillways, riprap, splash plates, or other demonstrably effective means.
(f) Matting or approved temporary ground cover shall be used to control erosion until natural vegetative ground cover is successfully established.
(6) Development, construction, and uses shall not directly or indirectly degrade surface water and groundwater through the introduction of nutrients, fecal coliform, toxins, and other biochemical substances.
(7) Prior to the approval of development, construction, or uses within a designated stream corridor, any existing source of biochemical or thermal degradation identified as originating on the project property or on contiguous properties of the same ownership shall be corrected.
(8) Facilities which use fertilizers, pesticides or herbicides shall use landscaping, low-risk products, application schedules, and other protective methodology to minimize the surface and subsurface transfer of biochemical materials into the stream corridor.
(9) Modifications to natural channel gradient, channel morphology, drainage patterns, and other stream features shall not permanently alter or obstruct the natural volume or flow of surface waters.
(10) Development, construction, or uses within the stream corridor shall not alter or divert flood flows causing channel shift or erosion, increase or accelerate the flooding of upstream or downstream flood hazard areas, or otherwise threaten public or private properties.
(11) Wells located within a stream corridor shall be protectively lined and installed in a deep aquifer with an acceptable minimum hydraulic continuity with either surface waters or a shallow aquifer.
(12) Structures placed in close proximity to the outer edge of bends in stream channels identified as having a high potential to meander shall be located to minimize the hazard from stream undercutting and stream bank erosion stemming from potential future stream migration.
(13) Adjacent communities and the Department of Ecology shall be notified prior to any alteration or relocation of a watercourse and evidence of such notification shall be submitted to the Federal Emergency Management Agency.
(14) Require that maintenance is provided within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.
(15) Development, construction, or uses within the hydrologically related critical area that would contribute to the degradation of the functions and values shall be avoided or mitigated using mitigation sequencing as outlined in Section
16C.03.10 (Mitigation Requirements).
(16) Development shall not obstruct, cut off, or isolate stream corridor features.
(17) Nothing in these regulations shall constitute authority of any person to trespass or in any way infringe upon the rights of private ownership.
(18) If archaeological resources are uncovered during excavation, developers and property owners shall immediately stop work and notify Yakima County, the Washington State Office of Archaeology and Historic Preservation and any affected Indian tribes. Archaeological sites are subject to RCW
27.44 (Indian graves and records) and RCW
27.53 (Archaeological sites and records), and development or uses that may impact such sites shall comply with WAC
25-48 (Archaeological Excavation and Removal Permit).
(19) The provisions of Chapters
16C.05.20 through
16C.05.72 of this title shall also apply to the development of lots and the placement, construction, or installation of structures in floodways and floodplains.
(20) Any portion of the vegetative buffer temporarily damaged or disturbed as a result of construction activities (excluding approved permanent use areas) shall be repaired at the completion of construction using reclamation standards in Section
16C.06.23 (Reclamation).
(21) Projects located within the floodway must meet the requirements of 16C.05.36.010 (Floodway – Permitted Uses).
(22) Projects within a floodplain must meet the requirements of Section 16C.05.28. (Flood Hazard Protection Standards) and 16C.05.32 (Floodway Fringe Uses).
(23) Changing from an existing use or development which does not meet the provisions of this chapter to a new use shall be reviewed in light of the following:
(a) The conversion will demonstrably reduce impacts to stream corridor and other hydrologically related critical area features; and
(b) The conversion will restore and/or enhance the functional properties outlined in Section
16C.06.05 (Functional Properties).
(Ord. 13-2007 § 1 (Exh. A)(16C.06.11), 2007; Ord. 5-2017 § 2(C) (Exh. 1) (part), 2017)