An assessment of wetland impacts and compensatory mitigation in the Cuyahoga River Watershed, Ohio, USA

Published source details Kettlewell C.I., Bouchard V., Porej D., Micacchion M., Mack J.J., White D. & Fay L. (2008) An assessment of wetland impacts and compensatory mitigation in the Cuyahoga River Watershed, Ohio, USA. Wetlands, 28, 57-67.
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This study is summarised as evidence for the following.

	Action	Category
	Require mitigation of impacts to marshes or swamps Action Link

Require mitigation of impacts to marshes or swamps

A study in 1995–2004 in Ohio, USA (Kettlewell et al. 2008) reported that 23 development permits requiring mitigation of impacts to wetlands prevented the loss of wetland area, but not habitat types or wetland number. Mitigation was carried out for all 23 permits. For two permits, compensation involved preserving existing wetlands. The other 21 permits mandated 27.8 ha of wetland restoration/creation as compensation. In practice, 26.3 ha of wetlands were restored/created, compared to 15.0 ha lost due to development: a net gain of 11.3 ha. However, 8 of 12 projects examined in more detail failed to restore/create the area mandated in their permits. Further, compensation in these projects was rarely “in kind”. Restored/created wetlands were mostly marsh (83% by area), whilst the impacted wetlands were a mixture of shrubby or forested swamp (57%) and marsh (43%). The 12 projects also restored/created fewer wetlands (65) than were impacted (134). Methods: The 23 permits in this study were issued between 1995 and 2003 for activities impacting wetlands. The permits were issued under the Clean Water Act. Information was taken from permit documentation and from field surveys of restored/created wetlands in summer 2004. Estimates of wetland area included some aquatic habitats (open water/submerged vegetation) and some existing natural wetlands incorporated into restoration/creation sites.

(Summarised by: Nigel Taylor)