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Additional Keywords: GMA, gravel, geomorphology, hydrology Data Package available at http://odp.trrp.net/Data/Packages/PackageDetails.aspx?package=62 Executive Summary: Measurements of sediment transport (bedload and suspended sediment load) were collected at four sites during a high flow dam release on the Trinity River in May 2013. Water Year 2013 was a “Dry” water year type as classified by the California Department of Water Resources (DWR). Typical for a Dry Year, 453,000 acre feet of Trinity River water were allocated for restoration releases. The resulting hydrograph included a two-day peak flow bench of approximately 4,300-4,500 cfs. Water Year 2013 was the third year (with a similar volume allocation and peak flow magnitude and duration) monitored under the auspices of the Trinity River Restoration program since 2004. 2007 and 2009 were also Dry Water Year types. By comparison, the 2011 Spring Flow Release provided the highest flow release yet made by the program: 11,600 cfs peak flow (a Wet Year with an allocation of 701,000 acre feet). As per the agreement between the Trinity River Restoration program (TRRP) and Graham Matthews and Associates (GMA), the level of effort in typical Dry Water Year flow release is considerably less than in wetter years with larger magnitude flow releases. A total of 18 bedload and 16 suspended sediment samples were collected at the four mainstem sediment transport monitoring stations: Trinity River at Lewiston (TRAL), Trinity River above Grass Valley Creek (TRGV), Trinity River below Limekiln Gulch (TRLG), and Trinity River at Douglas City (TRDC) over the course of the flow release. The four day monitoring effort spanned from May 1, 2013 to May 4, 2013. Crews sampled two sites per day and (generally) collected one two-pass bedload sample, one two-pass suspended sediment sample and a water surface slope measurement at each site each day. Continuous turbidity records were collected at three of the four sites (none at TRAL due to the very low turbidity which occurs in the short distance downstream of the dam) for use as a surrogate for computing continuous suspended sediment concentration. The TRGV site was also operated to collect continuous stage and develop records of continuous streamflow during the release. This is the one site where a USGS gage is not co-located with the sediment monitoring sites. Three discharge measurements were collected at the TRGV site between April 15 and July 31 (using ADCP equipment) and used to develop and shift rating curves for continuous record computation. Computed suspended sediment loads ranged from 136 tons at TRAL, to 607 tons at TRGV, to 830 tons at TRLG, and to 2,686 tons at TRDC. Total computed bedload ranged from 61 tons at TRAL, to 96 tons at TRGV, to 66 tons at TRLG, and to 1,274 tons at TRDC. The percentage of fine and coarse fractions within total bedload varies considerably by site, as 26 percent of the total bedload at TRAL was in the fine (0.5-8mm) size fraction, while TRGV had 59 percent; TRLG had 91 percent, and TRDC 66 percent. The coarse bedload transport was anomalously low at TRLG (6 tons), as was the case in 2012. The computed >8mm bedload for all sites were smaller than the last (2009) Dry Year type release and were more similar to the 2007 bedload magnitudes. At some sites, bedload discharge held fairly steady across the flow bench (or even increased such as at TRDC), suggesting that even in very low flow type releases, some falling limb data must be collected in order to more accurately compute sediment loads.