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Issue link: http://read.dmtmag.com/i/648999
28 City Trees The astounding growth of Columbia, Missouri from a sleepy Midwestern college town of just 62,000 residents in 1980 to over 118,000 today has predictably led to some growing pains. The additional roads, roofs, and other impervious surfaces associated with this rapid urbanization have dramatically increased surface runoff and negatively impacted the ecosystems of our local streams and creeks. The rush of storm water which now accompanies almost every downpour increases local stream flow or stream "flashiness" in our community, creating problems which directly influence the network of Columbia's multi-use trails located in the riparian forest corridors. Channel erosion and bank destabilization are the primary evils; however, log jams and debris piles are also a headache, espe - cially around trail bridges and support structures. A recent instance of costly channel erosion occurred in late June of 2015 after heavy rains. Approximately 150 feet (46 m) of the Hinkson Creek streambank collapsed, toppling trees and nearly severing access to Columbia's premier fitness trail, the MKT. Almost 1400 tons (1270 metric tons) of boulders were needed to stabilize the bank, and over 36 tons (33 metric tons) of topsoil were spread along the crown of the bank before we replanted with Streambed restoration on Hinkson Creek in Columbia, Missouri. The crest of the bank was seeded with river oats (Chasmanthium latifo- lium) and planted with stoloniferous (suckering) multi-stem native shrubs such as elderberry (Sambucus canadensis) and staghorn sumac (Rhus typhina) to quickly establish a network of anchoring roots. The creek has since been slowly depositing silt in the gaps among exposed boulders, which will allow Columbia to plant this rocky bank with sandbar willow cuttings this spring. Photo by Brett O'Brien a mixture of native tree and shrub species. Sandbar willow (S. interior) cuttings will be planted among boulders later this spring to complete the remediation. The other aspect of channel erosion, dislodged streambank trees, has also presented challenges over the years. During a flash flood event in 2009, the remains of a massive cottonwood collided with a trail bridge over the Hinkson Creek (see photo at right). A large branch of this floating tree punched through the steel railing and became entangled with the bridge structure. Removal work pro - ceeded with great care, since trees deposited in this manner are often under unexpected tension. Predictions have Columbia gaining another 20,000 residents by 2025, so it's unlikely that storm water or flooding issues will be going away any time in the near future. Fortunately, a broad consen- sus among Columbia's community stakeholders makes enhancing our natural resources and mitigating storm water a top priority. See the following link for more on these local efforts: http://helpthehinkson.org/CollaborativeAdaptiveManagement.htm —Brett O'Brien, Natural Resources Supervisor, Columbia, Missouri