Successful land development for the University will require the ability to meaningfully change and reduce the cumulative impacts to the water and land resources within its boundaries. It will also require a comprehensive management process to lead the implementation of measures that are outlined in the Plan. New strategies for the existing and proposed development at the University of North Carolina at Chapel Hill are proposed to restore and sustain the hydrologic balance. These strategies inciude protection and re-establishment of areas critical to the hydrologic cycle and by approaches to project planning, design, and construction that increase groundwater recharge and promote water quality.
As development plans proceed at the University, it will be important to require design and engineering consultants to be familiar with the Comprehensive Master Plan and its environmental directives. Sensitive design during the planning and design development process before construction is critical. New design projects, as well as retrofit design, should demonstrate the integration of these directives — including protection of environmentally critical areas and alternative stormwater management plans.
- Require mitigation for all environmentally critical areas that must be built on, or for any sub-basin that is already over 50% impervious.
- Minimize grading by fitting the building to the site, not the site to building.
- Limit disturbance and soil damage and the removal of natural vegetation in site design and location of the building.
- Site lawns only on flat or terraced areas.
- Minimize Impervious and Semi-pervious surfaces by:
- Reducing new road and building coverage.
- Reducing lawns to essential areas.
- Convert impermeable surfaces to permeable ones by replacing them with vegetation, porous paving, or other porous materials.
- Restrict high maintenance “gardens” to designated “sacred” landscapes; for example, the Bell Tower, the Coker Arboretum and the Rose Garden at the Planetarium. Such gardens work well on the tops of garages where large canopy trees cannot be planted.
- Reduce pesticides and chemical fertilizers.
- Use integrated peer management and organic soil amendments.
- Create an Environmental Management Plan.
Turf and the maintenance of turf is important within Main Campus, both as a “working surface” for athletics facilities and as part of the Campus green. However, turf is also used as an “all purpose” ground cover in many areas where it is difficult to grow and maintain. This is an expensive practice, as turf requires significant resources to maintain well. In many areas, such as steep slopes, excessively shady areas, and out-of-the-way places that receive little foot traffic, alternative planting types would have both an environmental benefit and reduce the maintenance needed. These kinds of plantings can still convey an elegant and well-cared-for appearance, which is appropriate with the image and “public face” of the University.
The initial analysis of stormwater impacts produced for the University of North Carolina at Chapel Hill Campus demonstrates quite clearly that a significant burden is imposed on the local stream drainage system, both in terms of increased volume and non-point source pollutants. What currently exists in terms of the few locations where detention basins have been constructed is inadequate to deal with either of these problems. The proposed additional development will only exacerbate these problems, without a major new strategy for stormwater management imposed on both the existing and new development landscape. A new system of both structural measures and non-structural land management practices will be required to prevent any increase in runoff volume and pollutant load, and in fact must go well beyond the proposed criteria to achieve any improvement over existing conditions.
A number of potential measures have been discussed during the course of the planning process. All of these proposed “better management practices” are intended to meet the storm water principles of runoff volume reduction, aquifer recharge, restoration of stream channel and floodplain, and water quality enhancement; but different combinations will be applicable in any given sub-basin. Most critically, all efforts should be made to infiltrate stormwater runoff in the uplands where the soils are suitable. In those sub-basins that are highly impervious, such as the Hospital area or east branch of Meeting of the Waters, very little open land remains in which to apply infiltration technologies. If at-grade solutions are not feasible, structural measures in the building itself, such as vegetated roof systems that retain rainfall and return it to the atmosphere as evapotranspiration, may be the on y option available. Some of the measures that are expected to meet the program criteria include:
- Creation of aquifer infiltration beds under large areas of pavement with pervious surfaces.
- Collection of stormwater (including roof drainage) in cisterns for reuse in irrigation.
- Construction of green roofs to store, evaporate and transpire water.
- Design of infiltration beds as vegetated planting strips along streets and in open areas.
- Requirements of building setbacks to provide a continuous mass of green facing the Campus streets.
No single solution will accomplish all of the volume and water quality goals, but the process begins by asking the question, “What can be done with in any given portion of the University to restore the natural drainage system?”
- Identify sensitive environmental areas on each individual site; include swales and all natural drainage features, the root systems of significant trees and natural forest vegetation.
- Require project architects and consultants to provide protection methods. Specify site protection in contracts that includes financial motivation for the contractor.
- Require the contractor to post adequate bond to pay for damage to the landscape.
- Designate access routes and storage areas that avoid sensitive natural areas and the trunks and root systems of individual trees.
- Use hand trenching for utility lines or re-route to avoid trees and their root systems.
- Identify, inventory, and map all significant old canopy trees, snowing the actual driplines of the tree canopy. Protect tree trunks with boarding, and protect canopy driplines with construction fencing.
- Avoid compacting soil where there is important vegetation to remain or to be reestablished. Protect tree root systems from being driven over by heavy equipment.
- Use silt fencing to protect drainage swales and steep slopes from erosion.
- Place construction fence just above the break of the slope and use construction fencing to prevent dumping and trespassing by vehicles and people.
- Monitor and repair construction fences on a daily basis.
- Replace missing heritage trees in greens of the Historic Core with new American forest canopy trees.
- Daylight buried streams, where possible, by taking them out of pipes and restoring them to open, free flowing channels with floodplains.
- Recreate wetlands in floodplains for flood storage and biofiltration.
- Restore forest cover on steep slopes.