STREAM RESTORATION IN HIGHLANDS RANCH 25 YEARS IN REVIEW

摘要

In its 25th year of existence, Highlands Ranch, Colorado is over 80 percent built-out, providing a community for approximately 80,000 people and businesses. Over the course of rapid residential and commercial development, this master planned community has dedicated vast open space corridors along the majority of their drainageways. Preventing the encroachment of development into these drainageways has alleviated many of the typical floodplain concerns and has established a great setting for recreational users and wildlife habitat.However, increased runoff caused by dense development has placed a lot of pressure on the steep natural channel systems and as such, has posed numerous challenges in stabilizing them. Stream restoration protocol within Highlands Ranch has evolved over the past quarter century due to advances in technology and the need to adapt to a wide range of channel characteristics throughout the differing drainage basins of Marcy Gulch, Big Dry Creek, Dad Clark Gulch, Spring Gulch, and other smaller systems.Varying conditions related to channel gradients, channel geometry, flow rates, soil types, vegetative cover, groundwater levels, and recreational needs have led to the construction of several types of channel stabilization improvements. Conventional grade control methods using soil cement, sculpted concrete, and grouted boulders have been utilized along with newer experimental techniques such as low flow riffle/pool channel linings and fully vegetative channel bed reinforcement systems. Depending on the project size and state of degradation, implementation of these improvements has ranged from low cost/low disturbance design-build approaches to multi-million dollar massive channel overhauls. Completion of such projects has also utilized community volunteers to install vegetative and low impact improvements.Utilization of the innovative stabilization techniques associated with the projects discussed in this presentation has resulted in healthy drainageways that have been embraced as a community amenity and a means of advancing the ever-changing field of stream restoration.