Title: Atlantic white cedar establishment success stroties – A reevaluation of landscape position, hydrology, and urban pressure in the context of a functional restoration model.

Authors: Joe Arrowsmith, PE, Underwood & Associates, Inc. (joe@ecosystemrestoration.com)

Speaker: Joe Arrowsmith, PE, Underwood & Associates, Inc. (joe@ecosystemrestoration.com)

Abstract: A combination of increased impervious surface cover, runoff pollution, outdated stormwater infrastructure, and wetland drainage practices have transformed the coastal plain landscape of Maryland thus endangering the sustainability of Atlantic White Cedar (Chamaecyparis thyoides) (AWC). Land conservation alone no longer offers assurance of species protection given permanent landscape-scale manipulation of the watershed and groundwatershed. For the past 20 years, Underwood & Associates have pioneered sand seepage wetland techniques which directly manipulate and correct both surface and near surface hydrology towards the establishment of a target high quality wetland ecotype anchored by the Atlantic White Cedar. This technique has been adapted for success as a wetland establishment practice in uplands, as a functional conveyance system along steep slopes, and as a restoration and enhancement method in lowland valleys. Successfully regenerating stands of AWC have been established in sites that historically were considered exceptionally flashy, exceedingly urban, high in the watershed, and generally poor quality. The ultimate example would be the use of sand-seepage AWC wetlands as a viable technique for retrofitting decommissioned stormwater management ponds. With the recent availability of watershed restoration funding derived from federally mandated water quality goals, real capital is available to invest towards establishment and recovery of AWC.  This report provides a retrospective overview of sand seepage wetland projects completed by Underwood & Associates over the past 20 years with particular focus given towards projects featuring AWC successes in atypical landscape positions, and those that were funded through municipal water quality mechanisms.

Keywords: sand seepage wetland, Atlantic white cedar, hydrology, restoration

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