Horizon conducted several technical studies of Lake Temescal and its contributing watershed to evaluate sediment loading into the lake. This work was conducted for the East Bay Regional Park District to develop alternatives to restore lake capacity and improve water quality. Horizon’s evaluation included analyzing multiple data sources to identify sediment sources and sediment transport rates (yield) into the lake, sediment storage rates prior to lake delivery, sediment accumulation and dispersion patterns in the lake, and degree of sediment carried through and out of the lake. Bathymetric surveys of the current lake were compared to historic maps to derive an understanding of net volume reduction in the lake over time.
In addition to studying sediment and erosion sources in the contributing watershed, Horizon evaluated dredging options to restore lake volume and water depth to improve lake water quality. Horizon’s technical studies are being used to evaluate how ongoing sedimentation into the lake could be managed to preserve and enhance lake water quality and aquatic habitat value over time. Horizon worked closely with prime contractor Anchor QEA on this important project. Horizon’s studies were highly valued by the District and helped the District move forward with considering options to improve lake conditions.