This study examined nonpoint source pollution via tributaries to Pineview Reservoir. Since few literature values of export coefficients are available for snowfall-dominated watersheds such as Pineview, locally scaled rates were quantified using an upstream-downstream bracketing technique. Nitrogen and phosphorus grab samples were manually collected and discharge measurements were conducted during the annual study period. Additionally, high-frequency monitoring sensors that measured EC, temperature, turbidity, and water level were deployed at the up- and downstream sites to represent short-duration transport events and to examine watershed processes on a more representative time scale. Daily nutrient loads were estimated from grab samples and flow rates using the Rank- Data (RD) distribution method and, using surrogate relationships for discharge and total phosphorus (TP) concentration from high-frequency sensors, half-hour TP loads were calculated. Short-duration snow melt events were identified by turbidity spikes and increased air temperatures as well as, in some cases, hydrograph peaks. During these events, export coefficients from 0.31 to 0.54 g TP/ha/hr were observed for low and high elevation snow melt events. While losses to ground water were observed for one study reach, the study reach with positive load gains had annual export coefficients of 0.018 g TP/ha/hr from high-frequency loads and 7.5e-5 g NOx-N/ha/hr, 3.5e-6 g SRP/ha/hr, and 9.1e-6 g TP/ha/hr from RD loads. These rates were 1,000 to 2,000 times greater than available literature values typical of rainfall-dominated watersheds. This study showed the importance of erosive, snow melt events on nutrient transport and the need for high-frequency monitoring representing short-duration events for accurate estimation of export coefficients. Management strategies to reduce nutrients from tributaries should focus on erosion control in the Pineview Reservoir watershed.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-2382 |
| Date | 01 December 2012 |
| Creators | Carrigan, Lindsey DeBoer |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu). |
Page generated in 0.0017 seconds