He sent us a message as well:

“See the two excavators working on other side of bank?
They are preparing the tieback for Bendway Weir.

There is a wide bend with Pump House on inner bend, which at 5000 cfs, directs flows to outer bend.  This is what blew out the Gabions by causing an “end run”.  So the Bendway will redirect the thalweg back into center of the new Newbury Riffle.

We showed the construction folks new and cost effective construction techniques also.  We finally managed to get a loader on the job which really speeded up production.  Excavators are much more productive if they can sit and have rock delivered.

It rained cats and doggies the last day I was there.  The river got about 3 ft higher in few hours.  Quite a challenge to cross since rock is on left bank and Bendway is on right bank!!

The Job is about 1/2 done, we placed almost 3000 T of the 6000 T needed.

Great to be heading home after two weeks in Northern Malaysia – taming the Pedu River! Made a lot of new friends, many challenges, so hot and humid sometimes I thought I would burst and then 6″ of rain in an hour. Lots of typical “construction challenges ” too!

Brought new technology and new techniques – all well received. They threw a going away party for me yesterday, I felt the love!”

“[Finally] getting some rock delivered now, though we are still behind schedule.  Quite a weekend here, no work on Friday – but Saturday and Sunday very productive (in terms of placing rock for Newbury Riffle).  Punctuated by huge afternoon thunder storms.  Must have rained at least 6 inches in an hour this afternoon!!
We are about 1/3 complete, you can see if look carefully the riffle toe downstream and the crest now built upstream.  The crest and middle of weir will come up about another meter.
I’m teaching a course for area engineers on Tuesday morning, then a field trip out to the site.  Wedensday morning will be my last day as I fly out from KL on Thursday.  
In meantime Ill layout everything conceivable to guys and they can finish without me.”




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!

Don’t forget to subscribe to our site for messages for current news, events, and projects!

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 TYPE: Bluff Repair
and Stabilization




CLIENT/OWNER: Local Homeowner


TRM, Live Staking, Hydroseeding


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. 



  •  Anchored TRM: A three-dimensional, turf reinforcement mat (TRM) was draped over the cliff face and anchored (nailed) to the slope by driving pins with large washers through the TRM into the slope (see Fig. 20.2).  Workers rappelled down the bluff face on ropes to drive the pins.  Two-foot long anchor pins were inserted on 3-foot centers (see Fig. 20.3).


  • Live Stakes: Once the TRM was securely fastened to the slope, live willow stakes were inserted through the mat into the slope (see Fig. 20.4).  The near vertical inclination of the cliff face required that this installation be done by workers suspended by a rope and sling system from the top of the bluff.
  • Hydroseeding: A specially designed mixture was sprayed on to and through the turf reinforcement mat by workers suspended on ropes from the top using hand held spray nozzles (see Fig. 20.5).  The mixture consisted of Flexterra @ 4000#/ac, native grass seeds (Maritime mix), Jumpstart (Profile) humic acid, and BioPrime (Profile) mychorrizae.

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




  1. Bio-stabilization measures can be used effectively to repair and stabilize the face of coastal bluffs. Special anchoring provisions may be required when attaching a TRM to a near vertical slope face.
  2. The combination of an anchored TRM and live staking were used in conjunction with a site adapted hydroseeding mix to stabilize a bluff face.




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 today!

Thanks for Reading!!!

– The Dirt Time Team


Select your currency
USD United States (US) dollar