Adopt A Beach

Executive Summary of Results for Years 1996–2003

Introduction and Methods
The Adopt-a-Beach (aab) program has completed its eighth year as a study that monitors camping beaches in Grand Canyon. This program, sponsored by Grand Canyon River Guides, Inc., is implemented by a one hundred percent volunteer force of river guides, scientists, and nps personnel. Results are submitted to various agencies such as the Cultural Resources Program of the Grand Canyon Monitoring and Research Center (gcmrc). Results are also presented to the Adaptive Management Program so that private and commercial recreational interests are represented as stakeholders in Colorado River management as reported to the Secretary of the Interior.
Methods implement repeat photography and observational comments that document the condition of a selected set of Grand Canyon camping beaches from April through October of each year. The selected beaches lie within three critical reaches (Marble Canyon, Upper Granite Gorge, and Muav Gorge) of the river corridor. A critical reach is defined as an extended area in which camping beaches are sparse, small, and/or in high demand. Two recently added critical reaches (Glen Canyon and Lower Granite Gorge) will also help in understanding long term erosion and system-wide sediment distribution.
The program assesses visible change to beaches resulting from changing regulated-flow regimes, rainfall, wind, and human impacts. Volunteers for this program are unique in that they run the Colorado River many times in one season, and they are able to provide sets of repeat photographs for each study beach. To date, guides have produced over 1500 repeat photographs and associated field sheets having recorded the sequential condition of beaches throughout the commercial boating season, year after year. Research results include total change to beaches after being impacted by certain flow regimes, longevity of the 1996 Beach Habitat Building Flow (bhbf) deposits, change to individual beaches between monitoring seasons, and primary and secondary processes that cause change in camping beach area and quality.

Results and General Conclusions
Results of this study since 1996 show that beaches have continued to decrease in size system-wide, even after the High Maintenance Flows (hmf) of year 2000 and the Winter High Fluctuating Flows (whff) of 2003. From 1996–1999, the net effect of controlled flow releases from Glen Canyon Dam resulted in the continued winnowing of beachfronts, cutbank retreat, and loss of camping area. The highest number of beaches showing negative impacts from fluctuating flows were reported in 1997, at which time flows reached a maximum of 27,000 cfs. Erosion to beaches through years 1998–1999 continued, but effects were not as profound. This decreased magnitude of change through the years since 1996 reflects two geomorphic processes:
1) the increased stability of beach fronts as they attain an angle of repose.
2) decreased amounts of sediment that can be eroded from beaches. By fall 2001, most beaches that had initially gained area from the hmfs of 2000 had returned to their 1999 condition. These conditions persist today.
Many factors are contributing to long-term erosion of these beaches. Primarily, erosion from medium fluctuating flows that contain low sediment concentrations resulted in conditions that are similar to those before the bhbf of 1996.

Adopt-a-Beach 2004 Review and Update

Adopt-a-Beach remains strong, year after year, with a hundred percent adoption rate. There is no other project like this in Grand Canyon, where guides collectively take action and monitor an immensely important recreational resource. The main interest driving this project is simply this: hands-on understanding of how our world-class camping beaches are changing as a whole over time.
Many of us know that beaches or parts of them come and go from season to season. The Colorado River is a dynamic and non-static system and should be managed as such. The questions we are attempting to answer with this project are these:
1) Are we gradually losing our major camping beaches?
2) What are the causes of beach change?
3) How might these changes affect camping in Grand Canyon?
To illustrate changes since 1996, we chose photo pairs of the North Canyon beach (Figure 1). This site typifies the average response of popular campsite beaches to three important test flows imposed by the dam. In the following, we briefly summarize our findings about the first two test flows, and expound upon the third test flow since results have not yet been presented in the bqr:
1) The Beach Habitat Building Flow (bhbf) of 1996 was successful in building up over eighty percent of all beaches under study (n= 41). Campsites were built up in elevation across the main campsite and back up to the 1983 deposit (Figure 1a and 1b). Figure 2 summarizes the longevity of this deposit until our last photo comparisons were completed in 2003. Since the bhbf, beaches have steadily eroded to the point where about 65 percent of all sites have presently returned to (or are smaller than) their pre-bhbf size. Beaches came back temporarily in 2000 from the High Maintenance Flows. Since then, cumulative erosion from medium and high fluctuating flows, rainfall, and people have deteriorated the overall condition.
2) The High Maintenance Flows (hmfs) of 2000 were successful in rebuilding the beachfront of about sixty percent of camping beaches and depositing fresh sand to main camp areas below the 31,000 cfs zone (Figure 1c and 1d). This deposit lasted less than one year (Figure 2) as medium-high fluctuating flows and rainfall deteriorated the deposit. By 2001 beaches returned to the same state that existed in 1999.
3) The Winter High Fluctuating Flows of 2003 showed variable results in their strategy of conserving sediment. Out of 38 comparative photos from before and after these flows, 56 percent of beaches showed no change or very little discernable change in camp size, 18 percent showed an increase, and 21 percent showed a decrease. (We could not clearly determine change for five percent of beaches). Guides commented that a veneer of fresh sand was deposited on many low elevation bars, but was not enough to create a significant area change that would benefit recreation (Figure 1e and 1f). Other beaches were devoid of fresh sand and showed qualities of increasing “hard pan” and rocky areas.
Muav Gorge and Upper Granite Gorge showed mostly no change to beach size. Marble Canyon beaches, however, were impacted in a dynamic way that is not all negative. In this reach alone, the number of beaches showing an increase, decrease or no-change were equally distributed. All increases occurred on low elevation bars where rocky shorelines were now covered with sand. Beaches showing decreases were impacted at the beachfront where sand was typically stripped and re-deposited to create a submerged bar. Results in Marble Canyon were also compared to previous winter-period years. In this analysis beaches showed more overall erosion after each winter period of moderately low fluctuating flows compared to those following the Winter High Fluctuating Flows of 2003. Data suggest that the Winter High Fluctuating Flows are the lesser of evils, and that some eddy-stored sand is redistributed onto low elevation bars. Overall, we interpret this data as follows: this winter regime is acceptable for the duration of the “drought” when the Paria cannot deliver the sediment needed, and flood gates remain shut for the time being. However, we still need to assess 2004 data for repeat results.

Secondary processes contributing to erosion are listed here and are ranked according to magnitude of impact:
1) gullying and flash-flooding from rainfall
2) beachfront erosion from campers
3) wind deflation.
Some recreational area loss to is due to encroachment of vegetation, mostly tamarisk.
Campsite area and quality can be greatly enhanced by implementing bhbfs well above power plant capacity, given there is available sediment inputs from the Paria and/or Little Colorado Rivers. Over eighty percent of guides agreed that camping (useable space and quality) had improved dramatically during the Low Steady Summer Flows (lssf) that followed the spring hmf of 2000.
Moreover, camps that would normally be under water became available for consistent use. By spring 2001, most guides reported worse camping conditions. This is attributed to relatively higher fluctuating flow zones on beaches, rendering lower camping areas difficult to use, and creating eroded beachfronts that presently expose rocks. Lack of a lower camping area will inevitably force camping and recreation into higher zones and into the more fragile xeric desert zone where many archeological sites are located.
The results of eight years from this monitoring program show that the bhbf of 1996 was the most beneficial management action for replenishing and rebuilding beaches for campsite use. All other subsequent test flows produced small new deposits that only lasted for seven to twelve months, at most. These results suggest that any newly deposited sand transported within power plant capacity flows will be quickly eroded if followed by medium to high fluctuating flows. This was evidenced by three events:
1) High flows (the high of about 27,000 cfs.) following the 1996 bhbf eroded much of the new deposit at all beach sites through the summer of 1997.
2) Medium fluctuating flows following the fall hmf of 1997 stripped away the new deposit entirely by spring 1998.
3) Medium fluctuating flows following the fall hmf of 2000 eroded most of the new deposit by spring 2001. To date, less than thirty percent of beaches show evidence of high-elevation sand (above 30,000 cfs line) deposited by the 1996 bhbf.
Annual implementation of hmfs in spring and in fall would help preserve camping beaches by maintaining the beachfront. The whff (5,000–20,000 cfs) of 2003 has been the least damaging flow, as beaches did not lose as much beach area over the winter period compared to other winter periods in previous years. However, whffs should not be substituted for beach building and beach maintenance flows. A regimen of bhbf s that exceed power plant capacity followed by low fluctuating flows are needed periodically to rebuild campsite areas above the 30,000 cfs line. However, future bhbfs need to have enough sediment in the system so as to preserve Marble Canyon beaches and lessen impacts on lower beach areas (below the 20,000 cfs line) systemwide.

For questions or comments please contact Kate Thompson or Lynn Hamilton at Grand Canyon River Guides, Inc., Flagstaff, Arizona (928) 773-1075.

Kate Thompson

So, to answer the questions presented above:
1) Yes, our campsite beaches are steadily deteriorating without having had beach-building flows for at least eight years.
2) Beach impacts are cumulative from years of regulated flows, rainfall, recreation, and wind but the primary cause of continued beach erosion is fluctuating flows and the secondary cause is rainfall.
3) The repercussion of deteriorated beaches is more recreation pressure on an increasingly limited supply of campsites in critical reaches. This will inevitably force campers to encroach upon the Old High Water Zone (ohwz) and other fragile eco-zones that have not habitually been used for recreation and camping.
What Else Has Helped or Hindered
the Camping Situation?
Low fluctuating or low steady flows following an hmf (or potentially a bhbf) have provided more space for recreation and camping on beaches (not for making river time, but for enjoyment of camps). Availability of camping space allows for recreation to be concentrated next to the river and not in or near the ohwz. This indirectly protects the more fragile xeric and archeological zones that adjoin camping beaches.
The Little Colorado River has spiked at 20,000 cfs after periods of intense rainfall. In August of 2001, many beaches showed increases throughout the lower portions of Upper Granite Gorge and all throughout Muav Gorge. This pink flood deposit stuck around until the high fluctuating flows of the next season. The data demonstrate the benefits to beaches with sediment influx from a side stream (and cumulative side canyons) simultaneous with a mainstem flow increase.
Vegetation management, or lack thereof, is prominent in all photos. A cursory look at photos shows that non-native vegetation encroachment is a huge factor now. Without periodic “flood flows,” this will remain an issue of increasing importance as non-native seedlings take hold, mature, and occupy more camp space.
Available sediment for wind transport has helped in maintaining clean camps. Guides have reported that wind transports and deposits sand throughout camp. However, if no fresh flood sand exists for transport by wind, then scouring and deflation is inevitable in portions of camps. This latter process has been thoroughly reported by guides in non-spike-flow years, along with increases in red ant populations.
Guides and other participants have collected an impressive amount of photographic and observational data since the inception of the Adopt-a-Beach project in 1996. The photo record for the first time is complete in digital format and will be available for all to review on a website early in 2005. A comprehensive review of our camping beaches may in the future include a look at vegetation encroachment and closer collaboration with groups working both in the Canyon as well as in other locales. Look for the website link on the Adopt-a-Beach page at the gcrg site (http://www.gcrg.org/aab/ab.htm) and take a look at some of the work we’ve all done together. Keep in touch and tell us what you see. There is little doubt that the project will continue to foster a better understanding of that world down there we hold so dear. All who enjoy a sandy beach in the Grand Canyon will benefit from keeping those on the rim informed of the state of those beaches, our beaches.
Thank you all adopters and funders, which include the Grand Canyon Conservation fund (a non-profit, grant-making organization established and managed by the Grand Canyon river outfitters), the Grand Canyon Monitoring and Research Center, and individual contributors.

Kate Thompson & Joe Pollock