Here's another EXCLUSIVE update straight from John McCullah himself in Malaysia-
"Update from project
Sg. Pedu site is 9km below huge Pedu Dam. The reservoir touches Thai border.
The toe of Newbury Riffle is in, but the Rock Delivery is still too SLOW.
We Need to lay 500T per day, only getting 200 T per day. So we are way behind schedule.
The riffle has well graded stone (30” - 2”) well compressed. It will be over 120’ long riffle with crest 2 meters (6ft high) then we plans on one Bendway Weir upstream to direct flood flows onto Riffle. This river can get 125,000 cfs in winter !!! No wonder gabion check dam failed
Wing Leong and I have been there everyday!!!"
Looks like a lot of work, but a lot of fun as well! We will be in contact with John throughout most of his trip, and we will keep you updated as the project builds!
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Thanks for reading!
- The Dirt Time Team
Hello! This just in from the other side of the GLOBE!!!
John is in Malaysia with Wing where they are working on and Engineered Newbury Riffle and the first Bendway Weirs in that part of the world.
John says the first few day were filled with construction logistics - getting equipment lined up and visiting local quarries to get the right rock.
The project is about 30 km below a large dam near the border with Thailand. The purpose for the work is to raise the water elevation so a large series of pumps can utilize the river water for irrigation of farms and rubber tree plantations.
First thing was to dismantle an old gabion check dam that had been built to serve that purpose - unfortunately the river had “blown out” around the check dam.
Check out the HOT OFF THE PRESS PICS!!
More on the design and construction later.
PROJECT: OPAL CLIFFS
PROJECT TYPE: Bluff Repair
PROJECT SCALE: Small
CLIENT/OWNER: Local Homeowner
TECHNIQUES EMPLOYED: Anchored
TRM, Live Staking, Hydroseeding
GEOGRAPHIC LOCATION: Opal Cliffs
Drive, Santa Cruz, CA
GEOMORPHIC SETTING: Sea cliff subject to active erosion and periodic retreat. The Opal Cliffs-Capitola reach is characterized by an irregular shoreline backed by cliffs ranging from 35 to 75 feet in height. The coastal cliffs throughout most of the city of Santa Cruz and neighboring Capitola are composed of erodible sediments of the Purisma Formation (siltstone and sandstone) along with the Santa Cruz Mudstone. These sedimentary rocks are often capped by 6 to 20 feet of unconsolidated marine and non-marine terrace deposits. The horizon-tal bedrock stratigraphy is easily visible in exposed or bare sections of the cliffs.
SITE CONDITIONS AND PROBLEMS: The Opal Cliffs section of the coastline is at high risk from erosion, the narrow beaches provide little protection from wave attack at the base of the cliff. Urbanization and house building at the cliff top causes further sub-aerial erosion threats, viz., concentrated runoff and subsurface seepage from streets, drains, downspouts, and excessive lawn watering. The face of the cliff at the location of the residence was actively eroding and retreating (see Fig. 20.1).
Figure 20.1 – Coastal bluff before treatment
TREATMENT OBJECTIVES AND CONSIDERATIONS: As a result of the high erosion risk from wave attack large sections of the sea cliff are protected by struc-tures including sea walls and rock revetments. The base of the cliff at this location is protected by a sea wall and rock armor. The main problem appeared to be erosion and shallow sloughing at the face of the bluff. The goal was to arrest this erosion and stabilize the face. Adjacent stable sections of the cliff were well vegetated. If the face of the bluff was stabilized sufficiently this would allow the establishment of vegetation which in turn would help control erosion problems. There was insufficient evidence of emergent seepage at the bluff face to warrant installation of horizontal drains (hydraugers) on the bluff face or a trench interceptor drain atop the bluff.
OBSTACLES TO IMPLEMENTATION: The main obstacle to implementation was the need to work on a near-vertical slope which required the use of ropes and slings. A system was quickly developed, however, that overcame this challenge without the need for an elaborate scaffolding or support system.
PERFORMANCE EVALUATION: A vegetative cover was soon established that was initially held in place by the anchored TRM. This provided enough time for the live stakes to root and gain a toe-hold on the steep slope. Erosion and shallow sloughing on the face has been arrested (see Fig 20.6). Only time will tell whether this treatment will suffice in the long run, or whether other measures such horizontal drains and/or an interceptor trench drain will be required.
Figure 20.6 - Views of bluff site immediately after treatment
BENEFITS AND LESSONS LEARNED:
Brabb, E. (1997). Geologic Map of Santa Cruz County. US Geological Survey, Menlo Park, CA
This is another great chapter out of Bioengineering Case Studies . Please see to the previous link for information on ordering your copy today!
Thanks for Reading!!!
- The Dirt Time Team
PROJECT #20 – LOWER SULPHUR CREEK
PROJECT TYPE: Salmonid Stream Restoration
PROJECT SCALE: Moderate, approx 1 mile of stream realignment and habitat restoration.
CLIENT/OWNER: Sacramento Watershed Action Group (SWAG) and Co-ord Resource Management Group
-- Willow & Cottonwood Pole Planting
-- LWD & Rock Habitat Structures
-- Newbury Rock Riffle
-- Rock Vanes
-- Stream Realignment
GEOGRAPHIC LOCATION: Turtle Bay / Redding Arboretum, North Redding, CA
GEOMORPHIC SETTING: Sulphur Creek is a small, seasonal tributary stream to the Sacramento River. The watershed comprises approximately 3,000-ac with 7-mile stream length. The Sulphur Creek Watershed Analysis and Action Plan (SCWAAP), 1996, documented that the lower 2 miles of Creek can provide valuable salmonid spawning and rearing habitat if stream form and function can be restored.
SITE CONDITIONS PROBLEMS: The entire watershed, especially the in-stream sections, has been AND severely impacted by hydraulic mining and dredger mining in circa 1800’s and gravel mining and road/highway building in the early-mid 1900s (see Figure 20.1) Lower Sulphur Creek (approximately 1 mile) runs through the Redding Arboretum. This section had been dredged for gold (circa 1850s and 1920s) and some of the dredger piles had been subsequently mined for gravel (circa 1930-1950) thereby removing the gravel-sized substrate from the stream system and leaving cobble- and small boulder-sized piles of rock in the stream and flood plain. A very significant land use impact occurred in 1934 when Highway 273 was build. The new box culvert diverted the stream out of its’ historic channel and into the adjoining oak/savannah woodland.
Figure 20.1 - Site Conditions in the Lower Sulfur Creek Watershed
TREATMENT OBJECTIVES AND CONSIDERATIONS:
Prior to restoration the stream in this reach is severely aggraded. The stream gradient in this lower reach is very low – an ancient alluvial fan – therefore the streams ability to transport sediment and bedload is low. The historic land uses have exacerbated this problem because the stream has been diverted out of its original channel by the upstream highway box culvert and it has been diverted around and through the gravel mining tailings. Early gold mining “turned the channel upside-down” then gravel mining in the mid 1900s removed the gravel-sized alluvium. Subsequently, the creek was diverted into modified dredger areas. In summary, the pre-restoration condition was characterized by a channel with a convex-up stream bottom, choked with large cobble, severe bank erosion, and little to no bank vegetation. One 1000-ft section of the stream was nicknamed “the dead reach” for all the young escaping salmonid frye that died as the stream dried up (went subsurface) episodically (see Figure 20.2).
The primary objective for improving stream function was to re-align and mimic it’s historic plan form while excavating the excess bedload material. The secondary goal was to increase instream and riparian habitat. The plan for fisheries improvement was threefold:
Simultaneously, the SWAAP designated and prioritized watershed-wide projects intended to reduce erosion and sedimentation. The entire Sulphur Creek Restoration effort implemented by Sacramento Watersheds Action Group (SWAG) was conducted over an 11-year period, 1996 – 2007.
Figure 20.2 - The "Dead Reach" in Lower Sulphur Creek
Figure 20.3 - Schematic diagram of Newbury Rock Riffle
Figure 20.4 - LWD structured constructed from logs/rootwads, boulders,
and pole plantings for vegetative anchoring.
Figure 20.5 - Rock Vane built at beginning of project reach - to protect
Oak tree on left decending bank and to direct flows toward Newbury riffle
and restored reach.
Figure 20.6 - Dogleg excavation looking downstream. Outer bend
is nearly vertical; rock and log toe are being placed in preparation
for "Live Siltation."
Figure 20.7 - Dogleg rock toe and "Live Siltation" seven years after construction.
OBSTACLES TO IMPLEMENTATION:
The biggest obstacle to this project was the permitting process. The CEQA rules and guidelines were applied to this project as if it was a development instead of a self-mitigating restoration. All parties, the City of Redding and SWAG were inexperienced, therefore it took about 2 years and almost ½ of the restoration / implementation budget to permit the project. Eventually SWAG had to complete City / FEMA Flood Map revisions even though the restoration involved removing tons of gravel tailings from the floodplain.
Urban stream restoration activities seem to make regional flood planners nervous – unfortunately many commonly-used tools such as HEC-RAS do not accurately reflect the impacts of localized activities such as willow planting, rootwad / large woody material placement, or redirective methods such as rock vanes. HEC-RAS assumes that the channel bottom is essentially “fixed” while the restorationist wants scour pools, riffles etc. The localized scour and low flow incisions quite often compensate for placing some material in the floodplain.
Secondarily, State and Federal laws, which are interpreted and enforced by inexperienced regulators, is extremely problematic. For example, at one time a State Water Quality regulator advised the project supervisor to put silt fences in the stream and to line the channel bottom with erosion control mats. The regulator apparently failed to understand the nature of restoring aquatic and salmonid habitat. Future stream restoration projects which were regulated by State and Federal Agency staff familiar with, and supportive of, restoration activities went much smoother and resulted in maximum ecosystem benefits.
The Lower Sulfur Creek project is relatively complex and required careful co-ordination among its different elements and components. The system performed well during and after intense rainstorms and high velocity stream flows following construction. In spite of several instances of high water the protective structures and vegetation stayed in place and displaced erosive, high velocity flows away from the stream bank while preventing further erosion of the stream bank. Low flows are now diverted to the restored channel by a Newbury Rock Riffle on left diverts low flows to restored channel (see Figure 20.8).. Vegetation established well both atop the flood terrace and near the water’s edge. Channel degradation appears to have been arrested and sediment is being flushed through the creek to the Sacramento River. The salmonid fish habitat has been restored and frye are no longer trapped during low flows which are now diverted to the restored channel.
BENEFITS AND LESSONS LEARNED
The restoration of lower Sulfur Creek required the use of heavy equip-ment for restoration. The idea that heavy equipment could be used in or near seasonally dry or flowing streams, by skilled operators and careful planning was a paradigm shift that was achieved by tactful communication, frequent demonstrations, and performance monitoring. The fact that the Salmonid species returned was definitely beneficial.
One very important method (BMP) was developed and demonstrated for working in seasonally dry gravel-bedded streams, namely “Washing of Fines.” Running heavy equip-ment in a stream channel during the dry season will ultimately bring the finer sand and silt particles to the surface. These ‘fines” can cause water quality exceedance when the first winter storms come.
Figure 20.8 - Newbury Riffle on left diverts low flows to restored channel on right
6 years after project completion.
Washing fines is an “in-channel” sediment control method which uses water, either from a water truck or hydrant, to wash any stream fines, brought to the surface of the channel bed during restoration, back into the deep interstitial spaces of the gravel and cobbles, leaving clean cobble and gravel on the bed surface (see Figure 20.9).
Fig. 20.9 – Washing fines using high pressure hose from a water truck.
SWAG monitored the stream turbidity during the first precipitation events resulting in stream flow. The results were astonishing because the practice of “washing fines” most often resulted in reduced turbidity when comparing upstream and downstream values. Sulphur Creek, being an urban stream with extensive upstream disturbances, could actually be “cleaned up” by Washing Fines in the restored construction reaches.
Maslin, P.E., W.R. McKinney, T.L. Moo (????). Intermittent Streams asRearing Habitat for Sacramento River Chinook Salmon, Publication source????
NCHRP Report 544 – Environmentally Sensitive Channel and Bank Protection Methods, 2005, J. McCullah, D. Gray
E-SenSS - Environmentally Sensitive Streambank Stabilization Techniques, 2005, Salix Applied Earthcare, Redding, CA
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