Challenge. Preservation and protection of the natural resources and environmental features of Carlito Springs through the design and construction of a replacement spring box.

Solution.To address a springhead that was unprotected and generally unsanitary for public consumption, INTERA designed and constructed a new spring box that protects the spring water from pollutants and allows for testing to determine whether or not the spring water classifies as groundwater under the direct influence (GWUDI) of surface water. Our efforts included developing the design (30%, 60%, 90% and 100%), preparing contract bid documents (plans and specifications), providing bid assistance to the BCPRD for selection of a construction contractor, conducting inspections of earthwork during spring box construction, and documenting all project activities. We engineered the spring box system to capture and protect the flow and deliver it downstream for beneficial use. The spring box was designed for a sustained annual gravity-fed flow of 10 gallons per minute for water supply to the existing cistern, with excess flows piped into an existing pond system. The design and construction of the spring box required geotechnical investigation of the walls surrounding the springhead, given that they are near vertical and loosely shored with stacked stone in some locations. The walls were properly shored such that they do not pose a risk to park visitors. The design intermeshes the concrete spring box containment area with the bedrock and captures the multiple locations from which spring water originates from the spring face. Particular care was exercised to avoid impacts to the existing fractures within the bedrock to prevent modifying the path and volume of spring water. Carlito Springs is notable for its high quality vernacular architecture and gardens, which are characterized in part by making use of locally available materials and conforming to the existing topography. The new spring box is consistent with this tradition, and incorporates the stone that was excavated out of the spring into a series of low, terraced stone retaining walls adjacent to and above the spring box that serve as planters. The design also factored in the difficulties associated with transporting and storing materials and equipment during construction in this remote area.