During the present study, potential ecological risks of 2 heavy metals (Cu, Pb) and 3 explosives (TNT, RDX, HMX) were detected at a military gunnery range. Since a portion of the site will be submerged after construction of a flood control reservoir, a site risk assessment was conducted over 2 time points: existing conditions; and after flood control reservoir construction. Terrestrial plants, invertebrates, birds, mammals, and aquatic invertebrates were selected as affected ecological receptors. Potential non-carcinogenic risk was observed at only 1 terrestrial site for Cu and RDX for both time points. The ecological hazard quotient (EHQ) of Cu for terrestrial plants was 1.22. For terrestrial invertebrates, EHQ of Cu and RDX were 1.38 and 6.47, respiratory Aquatic environment EHQ increased to some extent after reservoir construction, but values were <1.0. Comparing EHQ before and after construction at the same site showed reservoir construction would not significantly increase the overall ecological risk, suggesting reservoir construction affected potential ecological risks at the study site, but changes were acceptable. Assessment uncertainties were identified and are discussed.