The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality parameters, including chlorophyll-α. Using a spectroradiometer, spectral signatures of chlorophyll-α and turbidity were located. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-α. Stations with high turbidity exhibited a reflectance peak shift towards the red spectrum, making it difficult to detect the chlorophyll signature. Derivative analysis of the reflectance signal at 590-610, and 720-780 nanometers allowed discrimination of this chlorophyll signature from those of turbidity (0.66 ≤ r^2 ≤ 0.99).

An analysis of algal biomass measured by chlorophyll-a concentration in Lake Texoma was performed as a part of a monitoring program to develop baseline environmental data in order to detect the potential effects of engineered changes in chloride concentrations in the reservoir. This portion of the research project focused on two main research objectives. The first objective was evaluating the effect of sampling strategy on the ability to adequately reflect standing crop estimates and trends in algal biomass. Two sampling regimes utilizing replication of three versus ten samples were applied and then analyzed using a minimum detectable difference algorithm to determine the necessary magnitude of replication to represent the variation in the metric. Chlorophyll-a distribution was analyzed for zonation patterns expected in a river-run reservoir to establish the importance of representative sampling of river, transition and main lake zones of the reservoir for management decisions and trophic characterization.