ENVIRONMENTAL ISOTOPES FOR RESOLUTION OF HYDROLOGY PROBLEMS

The use of environmental isotopes as tracers in the hydrosphere is inc reasing as analytical instrumentation improves and more applications a re discovered. There exists still misconceptions on the role of isotop es in resolving hydrology problems. Naturally occurring isotopes in th e environment describe hydrological processes, estimate ages, fingerpr int sources and pathways, yet are not subject to the regulatory restra ints of artificial isotope injections nor the Limited extent of many c hemical tracers, particularly dyes and particulates. A shea review is presented for practicing hydrologists on the basis for employing stabl e and radioactive isotopes and a synopsis of recent isotope hydrology applications is provided. Special focus is presented on the emergent r ole of water isopopes (O-18, H-2, H-3) in wet-weather flow research in urban watersheds. A brief technical approach for an experimental site in the Mill Creek Watershed, Ohio is outlined.