93 WETLANDS
Table 22.93.A Mitigation Ratios | ||||
|---|---|---|---|---|
Category and Type of Wetland | Reestablishment or Creation | Rehabilitation** | 1:1 Reestablishment or Creation (R/C) and Enhancement (E) | Enhancement Only |
All Category IV | 1.5:1 | 3:1 | 1:1 R/C and 2:1 E | 6:1 |
All Category III | 2:1 | 4:1 | 1:1 R/C and 2:1 E | 8:1 |
All Category II | 3:1 | 8:1 | 1:1 R/C and 2:1 E | 12:1 |
Category I Forested | 6:1 | 12:1 | 1:1 R/C and 10:1 E | 24:1 |
Category I based on score for functions | 4:1 | 8:1 | 1:1 R/C and 6:1 E | 16:1 |
Category I Natural Heritage site | Not considered possible* | 6:1 rehabilitation of a Natural Heritage site | Case-by-case | Case-by-case |
Category I Bog | Not considered possible* | 6:1 rehabilitation of a bog | Case-by-case | Case-by-case |
* Natural Heritage sites and bogs are considered irreplaceable wetlands, and therefore no amount of compensation would replace these ecosystems. Avoidance is the best option. In the rare cases when impacts cannot be avoided, replacement ratios will be assigned on a case-by-case basis. However, these ratios will be significantly higher than the other ratios for Category I wetlands. |
** Rehabilitation ratios are based on the assumption that actions judged to be most effective for that site are being implemented. |
Protected Wetland Area Do Not Disturb Contact City of Fircrest Regarding Uses, Restrictions, and Opportunities for Stewardship |
Table 22.93.B Wetland Buffer Requirements for Western Washington | ||||
|---|---|---|---|---|
Buffer width (in feet) based on habitat score | ||||
Wetland Category | 3 – 4 (Low) | 5 (Medium Low) | 6 – 7 (Medium High) | 8 – 9 (High) |
Category I: Based on total score | 75 | 105 | 165 | 225 |
Category I: Bogs and Wetlands of High Conservation Value | 190 | 225 | ||
Category I: Forested | 75 | 105 | 165 | 225 |
Category II: Based on score | 75 | 105 | 165 | 225 |
Category III (all) | 60 | 105 | 165 | 225 |
Category IV (all) | 40 | |||
Table 22.93.C Required Measures to Minimize Impacts to Wetlands | |
|---|---|
Disturbance | Required Measures to Minimize Impacts |
Lights | • Direct lights away from wetland |
Noise | • Locate activity that generates noise away from wetland |
• If warranted, enhance existing buffer with native vegetation plantings adjacent to noise source | |
• For activities that generate relatively continuous, potentially disruptive noise, such as certain heavy industry or mining, establish an additional 10-foot, heavily vegetated buffer strip immediately adjacent to the outer wetland buffer | |
Toxic runoff | • Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered |
• Establish covenants limiting use of pesticides within 150 feet of wetland | |
• Apply integrated pest management | |
Stormwater runoff | • Retrofit stormwater detention and treatment for roads and existing adjacent development |
• Prevent channelized flow from lawns that directly enters the buffer | |
• Use low intensity development techniques (per PSAT publication on LID techniques) | |
Change in water regime | • Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces and new lawns |
Pets and human disturbance | • Use privacy fencing or plant dense vegetation to delineate buffer edge and to discourage disturbance using vegetation appropriate for the ecoregion |
• Place wetland and its buffer in a separate tract or protect with a conservation easement | |
Dust | • Use best management practices to control dust |
Disruption of corridors or connections | • Maintain connections to offsite areas that are undisturbed |
• Restore corridors or connections to offsite habitats by replanting | |
On-Site Density Transfer | |
|---|---|
Percentage of site in wetland | Amount of credit |
0 – 25% | 75% |
26 – 50% | 50% |
51 – 100% | 25% |