Your Dam Opinion Please 1

[BUGGAR]

I’m working on a drainage basin project in the Santa Cruz Mountains of California and I have come across a dam and reservoir that no one seems to know about. It is not on the list kept by the California Division of Dam Safety. Google Earth coordinates for the dam are Lat. 37.116474°, Long. -122.212653°.

There are some residences 2.5 miles downstream in the throat of the canyon at Google Earth coordinates Lat. 37.086769°, Long. -122.237904°.

I have notified the Division of Dam Safety and while I wait for their reply, I would like anyone’s engineering opinion on this. Thanks all.

 

[msquared48]

Looks like an old earth fill dam with a reservoir about 1500 feet long. Hass some kind of headworks too, and access road, but hard to see.

Mike McCann, PE, SE (WA)

 

[GeoPaveTraffic]

Good sized dam, wonder how dam safety missed it. I expect it will become a regulated dam very shortly.

Mike Lambert

 

[cvg]

Feature Detail Report for: Mill Creek 630 Dam
ID: 1663996
Name: Mill Creek 630 Dam
Class: Dam (Definitions)
Citation: U.S. Army Corps of Engineers. Dams and Reservoirs List, Washington, DC. 03-Mar-1981. A listing of impounded bodies of water and associated information.
Entry Date: 01-Jul-1994
*Elevation: 1509/460
*Elevations in feet/meters from the National Elevation Dataset
Counties
Sequence County Code State Code Country
1 Santa Cruz 087 California 06 US
Coordinates (One point per USGS topographic map containing the feature, NAD83)
Sequence Latitude(DEC) Longitude(DEC) Latitude(DMS) Longitude(DMS) Map Name
1 37.1166138 -122.2110792 370700N 1221240W Davenport

 

[cvg]

it is a relatively small dam, but is regulated by DSOD

Dams Within the Jurisdiction of the State of California
Dam No. 630-000
Name Mill Creek
Owner Private Entity
County Santa Cruz
Stream Mill Creek
Year Built 1889
Capacity (Ac-ft) 223
Res. Area (Acres) 12
Drainage Area (mi^2) 0.94
Crest Elev. (ft) 1487.3
Height (ft) 76
Length (ft) 250
National Type HYDF

 

[Yakman256]

How deep is the water behind the Dam? I had a Dam removal project where the storage area of the dam was all silted in and there actually wasn't that much water behind the dam. Removal of the dam was surprisingly easy from a permitting standpoint. Although, from the picture, it looks like it's deep enough.

 

[BUGGAR]

This project keeps getting better. First, thank you for the dam data that I should have found. Built in 1889 by hydraulic fill methods?? The dam is obviously being maintained and since it is a private owner, public information will be sparse. There has to be an overflow spillway or the dam would wash out. Who is using the water (huge issue in California right now)? As a CA Civil Engineer, the law allows me to enter private property in pursuit of my drainage design so I may schedule a trip to the beautiful Santa Cruz Mountains. I wonder if the Lonely Saddlebags Bar in Felton is still open.
I have the addresses of several of the residences in the canyon downstream. Mill Creek runs by their homes and obviously handles historical flows - the bridge below has not been washed out in years per CALTRANS. Would a dam washout be a possibility? Do I have a moral obligation here? I sure don’t have the budget. I think I’ll e-mail dam safety after I finish here.
Am I over reacting on the safety issue?
Thanks again.

 

[cvg]

why are you thinking there is a dam safety issue? the dam is regulated by the state dam safety department. it is a relatively small dam (less than 1 square mile watershed, 12 acre reservoir and only 200 acre-feet of storage is not large) and has been there for a 127 years. The state conducts annual inspections and requires an emergency action plan with inundation mapping which would identify a floodplain caused by a dam breach. If you are truly worried about your downstream project than you should do some due diligence and discuss with the area engineer.

http://www.water.ca.gov/damsafety/contact/DSOD_Contact_2015.pdf

 

[BUGGAR]

cvg: In progress. Will advise.

I'm also working with Water Quality Control Board and unfortunately there can be some lack of knowledge in some agencies.

Flint.

 

[chicopee]

Looking at Google Earth, it is interesting to note how someone would want to build a house at the bottom of a canyon, 2.6 miles downstream from the dam. No wonder Californians have all sorts of problems, no one is thinking through.

 

[BUGGAR]

Still waiting to hear back from Dam Safety.

 

[BUGGAR]

Still no response so I sent registered letter today.

 

[cvg]

We are dealing with the same area 5 engineer. he is in the field most of the time. you can get him at 12:05 when he comes in for lunch.

 

[BUGGAR]

I finally received their written response. It took some pressure to get this. Their reply was VERY guarded. The information they furnished was not complete.
I got what I needed so I am finished here.