Sediment Study of Addicks and Barker Reservoirs, Houston, TX

Abstract

2. Background a. Addicks and Barker Reservoirs

The Galveston District has managed and monitored Addicks and Barker Reservoirs in West Houston since 1949 (their completion). During that time there has been sediment influx into the reservoirs that has resulted in sedimentation within the reservoirs. The amount of sediment is largely unknown as is its exact location. Only recently has survey technology been adequate to measure this influx, however a general lack of historical survey data, and environmental influences such as subsidence has ruled out surveying to establish a baseline. The combined area of the reservoirs is ~26,000 acres. The quantification of the sedimentation rates will be conducted through the use of 239+240Pu geochronology.

b. 239+240Pu geochronology-Short Review

239+240Pu geochronology is a recent addition to the suite of short-lived and environmental radio-isotopes used for geochronology of recently deposited sediments. It is a bomb produced isotope and its application is comparable to 137Cs, but with the added advantage that it can be used on sand dominated sediments. In marine sediments, Kuelh et al. (2012) established that accurate sedimentation rates could be determined using plutonium isotopic geochronology in two independent sites. One site in New Zealand where Cs isotopic geochronology had failed previously and one site in Kitty Hawk North Carolina. Fig. 2 below is a graph taken from Kuelh et al. (2012) documenting their results in the N.C site. Additionally, they demonstrated its utility off of Galveston Island in sand dominated sediments.