Geography 642 May 2004 Project Partners: Jen Jackson, Vitad Pradith and John Prudhomme

Sausal Creek: Watershed Assessment

Site features and history The Sausal Creek watershed is located in the heart of Oakland, CA and drains 2,656 acres

(FOSC 2004) (see Figure 4). Sausal Creek flows perennially from the East Bay hills

starting at about 1,300 feet, westward through a broad coastal plain, and has its mouth at

the Oakland Estuary at sea level (Owens-Viani 1998). Its headwaters start as four

branches in the East Bay hills, including the Cinderella, Palo Seco, Scout Road and

Shepherd branches. Sausal Creek is similar to many East Bay streams in that it flows

through a number of different settings. While its headwaters are located on public open

space managed by the East Bay Regional Park District and its upper stream channel is

mostly open, downstream it is disturbed by culverts, golf courses, freeways and medium

to high-density neighborhoods.

Figure 5 shows the highly urban landscape surrounding Sausal Creek. Some 80,000

people live within Sausal Creek’s watershed, with estimated land use at 51% urban, 34%

urban-wildland interface and 15% dedicated open space and urban park (Lee et al 2000).

Surprisingly diverse patches exist within the watershed including mixed hardwoods,

redwood groves, coastal scrub, localized wetlands and annual grasslands (Lee et al 2000).

According to Friends of Sausal Creek (2004), some 250 plant species have been

catalogued and almost 80 species of birds have been sighted within the watershed.

Sausal Creek was likely named after the thickets of sausal or willow that the creek once

drained to at its mouth. The Ohlone inhabited the area and used sausal for weaving

baskets and fishing nets and for building huts. The watershed also supported alder, live

oak, big leaf maple, California wax myrtle, manzanita, currant, snowberry, California

buckeye, bay, hazelnut and wild plum (Owens-Viani 1998). Some of these plants and

trees may still be found today, but due to human disturbance exotic invasive species have

reduced the biodiversity in the area (Lee et al 2000).

According to Owens-Viani, several Spanish expeditions noted Sausal Creek on their

maps in the early 1800s, and in 1831 the first Europeans settled in the area. Impacts to the

watershed ensued as grazed livestock, cut timber in the upper watershed’s redwood

groves and imported invasive grasses. Later inhabitants capitalized on the rich alluvial

soils and planted numerous orchards which became known as the “Fruit Vale” area.

Others dammed the creek to sell drinking water to the growing East Oakland population.

By 1856 all the redwood trees in the watershed had been logged, increasing sediment

flows into the creek. The creek, once known to be lovely and babbling, became “unruly”

and a nuisance as people began to encroach on its floodplain and constrict its meander.

As more settlers built closer to the creek, projects to tame it and protect these homes

included concrete channels and culverts, check dams and walls. (Owens-Viani 1998)

To get a better idea of potential sediment flows into our reach, we completed a Sediment

Erosion Model (see Figure 7). The SEM shows great potential sediment loading upstream

of the restoration site and our study reach.

Despite all the decades of efforts to keep Sausal Creek in check, about half of it still

remains above ground and the creek itself maintains a riparian corridor through Dimond

Canyon and Dimond Park as well as in the upper watershed in San Joaquin and Redwood

Parks.

1987 was a turning point for Sausal Creek. That year, amendments to the Clean Water

Act spurred local governments to tackle non-point source pollution. Alameda County

soon had to comply with new National Pollutant Discharge Elimination System (NPDES)

permit requirements (Lee et al). In 1991, 17 entities (cities, Alameda County, flood

control agencies and water agencies) within Alameda County formed the Alameda

Countywide Clean Water Program and developed its first stormwater plan (ACCWP

2004). Since stormwater pollution comes from innumerable diffuse sources, the county’s

toolbox was limited to public education. Partnering with Aquatic Outreach Institute (now

called the Watershed Project), the ACCWP created a Watershed Awareness Program

(WAP) (ACCWP 2004). The WAP was a multi-year strategy to engage the public in

pollution awareness and prevention programs. The program centered on reconnecting

residents with their local creeks and watersheds with the idea that stewardship programs

would reduce contamination and assist the entities in the ACCWP comply with their

NPDES permits. Out of the WAP, Friends of Sausal Creek was established in 1996 (Lee

et al 2000).

Since 1996, Friends of Sausal Creek (FOSC) has helped to increase watershed awareness

by involving the local community in stewardship efforts (FOSC 2004). FOSC has

established a 30,000 square-foot native plant nursery and education center, lobbied for

repairs of sewer lines that leached contaminants into Sausal Creek, and has worked with

the City of Oakland Public Works department to restore a portion of the creek (FOSC

2004). The restoration project was completed in November 2001 (OPW 2004), by Wolfe

Mason Associates as shown in Figure 1.

The project involved restoring 597 linear feet of the creek (Chanse 2003), removing

concrete structures such as a small check dam and a spillway, creating meanders (see

Figure 1), bio-engineering the stream banks with willow stakes and brush layering and

placing soil erosion blankets (see Figure 2). A revegetation program has involved

thousands of volunteer hours and planting more than 20,000 native plants (OPW 2004).

The more natural banks and widened channel will hopefully allow the stream to have a

functional floodplain, improve filtering of contaminants, reduce sediment loading and

improve habitat. Populations of rainbow trout (ostensibly non-hatchery fish) inhabit the

stream, but no rare or endangered species are known to exist in Sausal Creek (OPW date

unknown).

For our watershed assessment project, we chose to assess a reach of Sausal Creek within

the middle watershed that runs through Dimond Canyon in Dimond Park. Our study

reach extended 450 feet upstream from the El Centro Ave culvert.

Figure 1. Sausal Creek Restoration Design (OPW 2004)

Figure 2. Brush layering in Sausal Creek Restoration Project (OPW 2001).

Figure 3. Concrete spillway removal – before and after (OPW 2001).

Study Objectives The purposes of this study were three-fold. Roughly in order of priority they were: 1. Assess the downstream impacts of the Nov. 2001 Sausal Creek Restoration Project While studying the restored reach was an option we considered, we decided that the ample community interest would probably mean the restoration project receives more than enough attention and oversight. What might be neglected, we felt, were the possible indirect affects of that restoration on other parts of the stream system. Basically we wanted to know if altering the upstream equilibrium had any affect on the downstream equilibrium, and if so what were those effects? For example, assuming the restoration project has diminished some of the bank incision and erosion that was occurring in that stretch (and according to Chanse 2003, it has), it follows that changes in erosion rates (i.e. increased incision and bank erosion) and possibly stream bed degradation (or at least, decreased aggradation) might take place down stream. Therefore the reach directly downstream from the restoration reach (and the last approx. 150 ft. of the restoration reach) was chosen for study as this area would likely see the greatest impacts. 2. Implement and practice watershed assessment skills and field methods Though we could have put the practical skills learned in the course to use almost anywhere, this objective actually influenced site selection considerably. Basically, we wanted to find a stream that would provide the best chance to utilize as many of the learned field methods AND overall watershed assessment skills as possible. In other words, we looked for a stream that had been negatively impacted in some way, had undergone restoration efforts, and had considerable variability in its geomorphology. 3. Build on existing data for future studies As noted, Chanse et al did a thorough examination of Dimond Canyon in 2003. One conclusion reached by this group was that it was still too early to tell if the WMA restoration project was successful in its intended goals. We thought it would be helpful then to build on this study by providing data and observations another year removed from project completion. Hopefully, as these studies are replicated in coming years, the cumulative data can help assess the success of the restoration project and, if necessary, suggest where other restorative efforts are needed. Methods Benchmark Establishment Our beginning landmark was at the end of the log pathway approximately 450 feet north of the El Centro culvert, our ending landmark. The elevation was determined using a Global Position System (GPS) taken at both landmarks and measured against a 10 meter digital elevation model projected in UTM NAD83.

Longitudinal Profile The results of our Longitudinal Survey are shown in Figure 8 and Table 1. Table 1 shows data gathered and Figure 8 illustrates longitudinal gradient of both the stream bed and water surface graphed in Excel. Of particular interest, pools and riffles were recorded along with other marked features. We observed braided channels, some minor undercutting, and algal blooms that hint of eutrophication. Cross Sectional Survey Three surveys were completed at 8.6’, 130’, and 392’ feet downstream of our starting point, as shown by Figures 9 and Table 2. According to Harrelson’s methodology, a perpendicular profile was derived recording critical features such as wet bank, bankfull, thalweg depth and water surface elevation. We selected sites because they were determined to be areas in flux and of potential future sites of erosion. Planview We drew sketches in tandem with the longitudinal profile. We recorded specific features such as bank vegetation, stream bed characteristics, general direction, and any interesting landmarks as shown in Figure 10. Other pertinent information included digital photos recorded as ‘photo points’ on the sketch for later referral. Pebble Count Two pebble counts were performed at Station 0 (0’) and at Station 8 (146.8’) to estimate the average pebble size and overall streambed characteristics. Our results are displayed in Table 3. The result at Station 0 and 8 estimated a D50 at 13 mm and 30 mm respectively. GIS Analysis GIS analysis was utilized two-fold: as a visualization tool and sediment erosion modeling using SHALSTAB (SEM) an ArcView 3.x extension. Visualization included the use of ArcGIS, Spatial Analyst, and 3D Analyst as illustrated in Figure 7. The SEM modeling incorporated a DEM and soils layer using appended K factors obtained from the City of Berkeley.

Figure 6. Sausal Creek Watershed

Figure 4. Location of Sausal Creek in relation to San Francisco Bay Area

Figure 7. Sausal Creek Sediment Erosion Model

Figure 5. Sausal Creek within highly urbanized environment

Figure 10. Plan View with reference photos.

Figure 8. Results from longitudinal survey

Sausal Creek Bed and Surface Elevation

182

184

186

188

190

192

194

0 100 200 300 400 500

Tape Distance (feet)

Elev

atio

n (fe

et)

Bed ElevationH2O Surface Elev

Table 1. Data collected during longitudinal study

Station ID Distance

Instrument Height Foresight Backsight Elevation Depth

Surface Elev Photo #

4.77 200 0 0 204.77 11.77 193 0.26 193.26 1429 1 47.2 204.77 11.79 192.98 0.11 193.09 2 61.2 204.77 12.06 192.71 0.28 192.99 3 85.3 204.77 13.13 191.64 0.5 192.14 1432&14344 99.1 204.77 13.72 191.05 0.82 191.87

TP1 5.4 12.8 1435 5 110 203.85 12.7 191.15 0.6 191.75 6 123.45 203.85 13.41 190.44 0.62 191.06 7 134.6 203.85 14.85 189 2.2 191.2 8 146.8 203.85 13.05 190.8 0.25 191.05 9 191.4 203.85 14.18 189.67 0.32 189.99

10 204.5 203.85 14.98 188.87 0.78 189.65 1436&143811 240.1 203.85 14.83 189.02 0.58 189.6 12 255.7 203.85 14.57 189.28 0.23 189.51

TP2 255.7 5.51 12.8 13 273 202.08 14.74 187.34 1.5 188.84 14 301 202.08 13.885 188.195 0.53 188.725 15 338.2 202.08 14.95 187.13 0.95 188.08 1441 16 362.2 202.08 14.41 187.67 0.35 188.02 1442 17 383.5 202.08 15.01 187.07 0.35 187.42 1445 18 399.3 202.08 16.17 185.91 1 186.91 1446&144719 424.7 202.08 16.15 185.93 0.25 186.18 20 460 202.08 17.66 184.42 0.7 185.12 end culvert

Table 2. Results from cross sectional surveys.

Cross

Section1

HI FS Tape length Notes Elevation Distance

5.18 4.68 19Top of flood plain 0.5 0

9.15 26 bankfull -3.97 7 11.77 29.5 left wet bank -6.59 10.5 12.29 32.6 thalweg -7.11 13.6 12.13 35.4 middle channel -6.95 16.4 11.94 41.1 rt wet bank -6.76 22.1 10.05 43.5 rt bankfull -4.87 24.5 6.44 55.5 flood plain rt -1.26 36.5 Cross Section2

5.12 5.12 46Top of flood plain 0 46

10.41 26 bankfull -5.29 26 12.39 21 left wet bank -7.27 21 14.7 13.5 thalweg -9.58 13.5 15.84 9.6 middle channel -10.72 9.6 12.59 7.6 rt wet bank -7.47 7.6 9.53 4.2 rt bankfull -4.41 4.2 4.68 0 flood plain rt -0.44 0 Cross Section3

5.04 5.03 0Top of flood plain 0.01 0

9.8 12.2 bankfull -4.76 12.2 13.33 18.5 left wet bank -8.29 18.5 13.9 20.5 thalweg -8.86 20.5 13.76 22.8 middle channel -8.72 22.8 13.18 26.5 rt wet bank -8.14 26.5 11.01 29.8 rt bankfull -5.97 29.8 7.74 38.5 flood plain rt -2.7 38.5

Figure 9. Results from cross sections

Cross Section 1 - Braided Channel at 8.6'

192193194195196197198199200201

0 5 10 15 20 25 30 35 40

Tape Distance

elev

atio

n

Cross Section 2 - Top of Pool at 130'

188

190

192

194196

198

200

202

0 10 20 30 40 5

Tape Distance

Elev

atio

n

0

Cross Section 3 - Riffle Near Culvert at 392'

190

192

194

196

198

200

202

0 10 20 30 40 5

Tape Distance

Elev

atio

n

0

Table 3. Pebble Count.

Station 0 -- 0 feet D50= 13 Station 8 -- 146.8

feet D50= 30

Lessons Learned

As could be expected for a first attempt, there were a number of things we felt we could

have improved upon throughout the assessment process. In no particular order, the first

was to research the watershed more thoroughly beforehand. Though adequate research

was done, time constraints didn’t allow for as thorough a researching process as we

would have liked. Secondly, for more accurate measurements, we would have chosen a

cloudier and less windy day. Both of these factors affected the accuracy of our

surveying, as sun glare and wind made sighting of the stadia rod difficult at times.

However, we didn’t think either of these affected accuracy to a significant degree.

Thirdly, we didn’t use a flow meter as part of the field methods, as it was not accessible

(broken?) and we felt this was a mistake. Clearly, this would have been the best method

of determining whether the restoration project was affecting flow rates, and therefore

could be accelerating downstream erosion and otherwise altering the stream system.

Fourth, it became clear once we looked back at our work and others’, the most neglected

part of our data recording/notetaking was our Plan View. Time constraints as well as

lack of experience were probably to blame for what was, in the end, an adequate but

incomplete Plan View. A little more time spent on it would have paid off for us, and

others down the road, in terms of locating features and being able to precisely replicate

the study. Finally, we felt better organization in the beginning would have made the

whole process more efficient and precise, perhaps affording more time for each task (like

the Plan View). For example, had we layed out our specific tasks on paper beforehand,

as opposed to operating from a mental plan, we may have avoided a time-consuming

return trip after pebble counts and a straight-line reach distance were left our of initial

assessment.

Future Study

It has been said that because of the critical role of floods in stream dynamics, a minimum

of thirty years of data on a stream is needed to assess its relative health. Given this

limitation, we knew going in that without much prior data to compare it against, a

“snapshot” assessment like ours would be probably be insufficient in terms of assessing

the downstream impacts of the restoration project. Short of visual evidence of major

accelerated erosion, any assessment of a change in stream dynamics must be done

methodically with careful measurements, over a period of years. Realistically then, an

assessment like ours can only be carried out as an ongoing study or in concert with follow

up studies. We knew this going in, and since we did not observe any major areas of

concern (though we noted some minor bankcutting), we accepted the fact that final

judgements on whether the upstream restoration had negative impacts on our reach would

have to wait for future study. For this reason future studies on our reach, as well as the

restoration reach are very important. Studies should be undertaken every two years if

possible and immediately following any flood years.

References Owens-Viani, Lisa. 1998. Sausal Creek Watershed: A Cultural and Natural History. Richmond: Aquatic Outreach Institute. Lee, Michael, Anne Hayes and Martha Lowe. 2000. Developing Community Based Stewardship of Urban Watersheds: The Case Study of Sausal Creek, Oakland, CA. http://www.isis.csuhayward.edu/alss/geography/mlee/ucowr00.ppt (last viewed on-line 5/14/04). ACCWP (Alameda Countywide Clean Water Program). 2004. Program Information. http://www.cleanwaterprogram.com/aboutus_home.htm (last viewed on-line 5/14/04). FOSC (Friends of Sausal Creek). 2004. Promoting Watershed Awareness http://www.sausalcreek.org (last viewed on-line 5/13/04). Chanse, Vikki. 2003. Along Sausal Creek: an assessment of vegetation, habitat and morphology of an adopted urban creek. Berkeley, CA: Water Resources Archive http://repositories.cdlib.org/cgi/viewcontent.cgi?article=1001&context=wrca (last viewed on-line 5/14/04). OPW (Oakland Public Works). 2001. Sausal Creek Restoration Project. http://www.oaklandpw.com/creeks/sausal_complete.htm (last viewed on-line 5/13/04). OPW (Oakland Public Works. Date unknown (likely 2000). Initial Environmental Review Sausal Creek Restoration in Dimond Canyon. Courtesy of Ali Schwarz, OPW.