© GTM Landscaping and Renovations - Designed by Biz Builders of NH Landscape design to cover culvert  - complete landscape make over. New Drainage ditch landscape design Concord NH, Meridith NH, Bedford NH, Dover NH, Manchester NH, Nashua NH, Goffstown NH, Portsmouth NH Drainage ditch before hardscape. Culvert with rock retaining wall. Drainage area abutting the street. Dark mulch with crushed stone drainage area.