GrokSurf's San Diego

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Posts Tagged ‘Groundwater’

A rocky search for water beneath San Diego

Posted by George J Janczyn on May 26, 2011

Last week Wes Danskin treated us to news (What’s percolating beneath San Diego?) on the new USGS deep monitoring well at San Diego Chollas Park (SDCP), part of a study of the geology and groundwater resources in the coastal San Diego area.

Here’s the latest from Wes’s log:

 

May 17: Every picture tells a story

Picture of our core at 580 feet depth

May 20: Sounds of silence

Drill rig broke yesterday; frayed the cable supporting the kelly head; dangerous not to replace; so we will.

A core we obtained from 665 feet; looks like Friars Formation to me

May 23: 875 feet, no, not yet

We all underestimated the depth to bedrock, even the drillers.

STATUS
Sunday night, at 875 feet deep. Maybe in the top of the weathered bedrock. Cuttings appear to be ground-up rock; drill times are longer, but not so long to indicate hard rock, I think. Taken cores along the way, every 150 feet or so, most recent: 440, 580, 665, 860 feet.

FUTURE
Will continue drilling, until we once again think we are in hard rock, probably the Santiago Peak Volcanics, then take a core, to make sure it is what we think.

I’d like to get 1 or 2 piezometers deeper than the production zone of National City well field, which has been producing fresh water for 50+ years. Bottom of those wells is about 700 feet below sea level; presently we are at 550 feet below sea level. Good news is we have covered the majority of the production zone, so if groundwater is flowing roughly horizontally to the coast, we will be able to sample the upgradient side of the flow field, or at least a similar flow field a bit north of the National City wells. Bad news is that drilling another 450 feet (150 to bottom of zone + 300 feet) will not be easy. But our drilling is about patience and flexibility. So we’ll see how it goes.

May 25: Bedrock and beyond

STATUS
Yes, we hit bedrock, finally, at 877 feet. And we have proof, as shown in the photo below (core of the Santiago Peak Volcanics, … same rock as what the coastal dams are anchored in). Note the fractures and related water deposits, such as calcite shown at the point of the pen. This deposit demonstrates water flow through the fractures, albeit, we don’t know when.

In the process of squeezing the sediment that we obtained via coring. Short answer I think is that the pore water is more saline (ec = 1800; tds = 1000) than I would have thought/hoped. A bit confused by why we are not seeing any 600 tds water like National City wellfield. Darn. Answer may change a bit when we install the piezometers in the more transmissive zones.

FUTURE
We’ll continue drilling in the bedrock with the goal of getting deep enough (200+ feet) to install a well, hopefully with sufficient fractures to yield water. I have a plan for 5 piezometers: 3 inch to the bottom to monitor changes in salinity and temperature; 2-inch for the other 4. Estimated completion without geophyscial logs, etc are:

	          5. Water table at 50+ feet, 
	          4. Below water table at maybe 250 foot depth in stadium conglomerate, 
	          3. Something in middle 400-500 foot zone, 
	          2. One in Friars formation at 700 feet, and
	          1. One at bottom in Santiago Peak Volcanics at 1000+ feet.

Core of the Santiago Peak Volcanics, same rock as what the coastal dams are anchored in

PHOTO BELOW. Bill Elliott, SDSU professor and local gravity/geology guru; and Adam Kjos, our local USGS man on the spot, supervising the drilling. Both are trying to figure out from the drill cuttings what might be going on, e.g.,

  1. What formation are we in, where
  2. Why the 600 feet thickness of stadium-like coarse deposits are present
  3. Whether sand at 700 feet might be the Friars formation, or something like it
  4. The weathered zone above the volcanics appears to be about 60 feet thick
  5. Do any of these geologic units really correspond to geologic units mapped at the land surface?

Thanks to Bill Elliott for coming to the drill site and sharing his expertise in local rocks to help us understand what we might have been drilling through, and to Dave Schug from URS for similarly stopping by, though I was not on site then to take photos and quiz him.

 

Postscript May 31, 2011

STATUS
Reached the end of the line, 1100 foot depth. Every well sort of tells you when it is done giving up secrets. When drilling took more than 3 hours 20 minutes for each 20 feet, we decided to call it a good effort. We have obtained much new information, and whatever else we could gain from drilling deeper into the Santiago Peak Volcanics, probably is better done at another location, starting in bedrock and using air rotary technique.

GEOPHYSICAL LOGS
After reaching 1100 feet, based on my request to get a good 100+ feet into the Santiago Peak Volcanics so that we can complete a well that will reliably yield water, we stopped, cleaned the well, and called in our geophysical logging experts over the weekend (never a holiday for anyone associated with drilling; got done logging at 3 am; thanks Tony and Mike).

The geophysical logs are attached so that you can see for yourself the variation in material. Don’t worry; you don’t have to understand the logs or what they mean to get the basic idea. When the squiggly line changes, that means the earth or the water quality has changed. So at a first level, big picture analysis, look to see where the lines change once or twice or three times in the span of 1100 feet. Bet you can pick out where the bedrock starts. Say 877 feet. Another package of material is from about 440 to 600; I’m guessing alluvial fan based on cuttings and drilling notes; and another unit, mostly sand, from 600 to the weathered bedrock at about 800. But the SP log shows two zones within that last zone, so again this is not so precise as to become boring, or a single answer wins. Will know more, or think we do, after several hours of analysis by several of us.

NEXT STEP
We’ll be starring at the geophysical logs, the cuttings, the drilling notes, the locations of core samples, and using our Ouija board to divine where to place the piezometers. Let you know in the next couple of days the precise well design.

In the meantime we are reeming the 7 7/8-inch pilot hole, first with a 13-inch bit down to about 350 feet to accommodate two piezometers above that level; then with a 10-inch bit down to 820 feet to accommodate 2 more piezometers above that depth, then with the 7 7/8 inch bit to clean out the debris that fell in the hole down to the total depth of 1100 feet.

The rationale for drilling a pilot hole first is that a smaller diameter hole can be drilled faster, circulation time is faster, the geophysical logs will be better, and there may be fewer problems with caving. The bad part is we will spend 4-6 days redrilling the well to make it the size needed to install piezometers. If we knew the geology ahead of time, then perhaps we could design the general size of the well bore ahead of time and only drill the well once. But in San Diego that knowledge does not yet exist. Getting there though. The geologic framework model that Carolyn and Claudia are preparing shows that we are getting to where drilling will be less wild-catting and more predictable engineering.

 

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What’s percolating beneath San Diego?

Posted by George J Janczyn on May 17, 2011

Wes Danskin, the Project Chief for the USGS San Diego Hydrogeology Project has been busy studying what’s going on underneath San Diego. Late last year he updated us with work underway at that time. Now he’s working on a new project with a deep USGS monitoring well:

———————————

May 15, 2011:

That time again. Another deep USGS monitoring well is being installed. This is the first in a series of updates.

WHO
The United States Geological Survey (USGS) is partnering with the City of San Diego. Many thanks to Greg Cross, George Adrian, and Marsi Steirer of the City Water Department and to Keith Selby and Mike Morrow of the City Park Department for their critically important help in getting this project going.

WHAT
A deep multiple-completion well is being installed to help define the geology and groundwater resources in the coastal San Diego area. This and prior USGS wells are described on the project website, http://ca.water.usgs.gov/sandiego. This well is referred to SDCP (San Diego Chollas Park).

WHEN
Started May 10, will continue through about June 10.

WHERE
Chollas Community Park, toward the westernmost end, just east of 54th Street. Drilling in the North Chollas Community Park parking lot, in a median between parking stalls, about 50 feet from a drainage from Chollas Lake.

WHY
To define the groundwater flow paths from the eastern part of San Diego County, to the western part where additional groundwater extraction likely would occur. The geochemical water samples that we have collected previously from coastal wells (stable isotopes of hydrogen and oxygen) suggest that the source of the groundwater is recharge from precipitation not on the alluvial plain of the coast, but further east, such as near El Cajon, or further east. This means that the groundwater would need to flow through hard rock (granites, and Santiago Peak Volcanics) in order to reach the coastal sediments west of about Interstate 805.

This well site in Chollas Park (SDCP) was chosen to be east of the La Nacion fault which is approximately 54th street. This site means the drilling will penetrate some unconsolidated sediment (maybe 500 feet), and then penetrate the hard rock. Ideally, the total depth of the drilling will be about 1500 feet. Completion of the well with about five 2-inch PVC piezometers will allow us to sample groundwater from different depths and better understand the groundwater flow system.

Another well site, referred to as SDHF is located at the intersection of Home Avenue and Federal Blvd, and is on the down-dropped west side of the La Nacion fault. These paired wells (SDCP and SDHF) will aid us in understanding groundwater flow from east to west across this major structural feature in San Diego.

SITE VISITS
Are possible by contacting me.

PROGRESS TO DATE
Will give more details in a subsequent email, but the short answer is that at about 2 pm on Sunday, we were at 410 feet in a sandy, clay, ready to take another core.

Rough stratigraphy, from my memory:

Depth — Geologic characteristics

10 feet — Sandy fill.

20 feet — Santiago Peak gravel. Scared us, thinking we maybe already hit bedrock, but it probably was gravel eroded from a construction project upslope.

40 feet — Stadium Conglomerate, or redeposited San Diego Formation. Hard drilling

100 feet — Really hard and slow drilling, scared us again; thought we’d hit bedrock, was just a hard boulder and a worn out bit.

150 feet — Stadium Conglomerate, wore out two bits so far (button carbide and tipped iron).

234 feet — Formational change to sand; obtained cores. Friar’s formation? Seaward facies of Stadium?

280 feet — Still in oxidized (red streaks) of sand with variably clay.

410 feet — Sandy clay, preparing to obtain another core. I lost my Depth to Bedrock pool; thought we’d hit bedrock by 312 feet. Monte’s gravity suggests about 480 feet.

May 16, 2011:

GOOD NEWS
We hit bedrock. We’re through the sediment, and drilling into bedrock (Santiago Peak Volcanics). Hit bedrock below 398 feet though admittedly it is a bit of a blur between zones of weathered bedrock and hard rock. We are down to 578 feet. We’ll take a core Tuesday morning to see what the material actually looks like. Water flowing into the well is limited so we are not finding highly pressurized bedrock, yet, with too much water to readily get rid of.

BAD NEWS
I may never live this depth-to-bedrock-predicted-by-gravity thing down.

DEPTH TO BEDROCK
Seems we found bedrock at roughly the depth predicted by Monte Marshall’s gravity map processed by Carolyn Glockhoff in our office. While I agree that gravity measurements are helpful at defining the general shape of a basin, which why I was eager to use Monte’s work, I’ve never been under the geophysists’ illusion that the gravity measurements are sufficiently precise to predict anything particular, much less depth to bedrock at a particular drill site.

But then when you have no alternatives, gravity makes sense to use; so we did. And it worked.

Wesley R. Danskin
Research Hydrologist
United States Geological Survey (USGS)
California Water Science Center
4165 Spruance Road, Suite 200
San Diego, CA 92101 USA
619-225-6100 office
wdanskin@usgs.gov

 

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Helix Water District holds public scoping meeting for groundwater recharge IPR project in El Monte Valley

Posted by George J Janczyn on March 9, 2011

El Monte Valley. El Capitan Dam is around the bend a couple of miles.

The Helix Water District held a public meeting yesterday to give notice that it is beginning preparation of an Environmental Impact Report (EIR) for the proposed El Monte Valley Project (or more completely, the El Monte Valley Mining, Reclamation, and Groundwater Recharge Project).

El Monte Valley lies just west of El Capitan Reservoir and dam, with the San Diego River channel running through its length. Beneath the valley is a groundwater aquifer that provides water to the Helix district and many valley residents with wells on their property. The project aims to recharge the aquifer with purified recycled water (aka indirect potable reuse, or IPR) that would be piped in from a facility in Santee and emptied into recharge basins to percolate into the ground. Some injection wells might also be used for the recharge process, which would raise the water table for the slowly depleting aquifer and provide the district with an additional 5 million gallons of water per day.

Other components of the project are a temporary (8-10 years) sand-mining operation that would help pay the cost of the project. Parts of the valley and river channel would then be graded, contoured, and restored for riparian habitat with native plants and trees and recreational features including hiking and equestrian trails.

Yesterday’s “Scoping Meeting” was held as an adjourned board meeting at the district’s La Mesa offices at 7811 University Avenue at 7pm. The primary reason for the meeting was to get feedback from stakeholders and interested persons about topics of concern they would like to have addressed by the EIR.

About 75 people attended this meeting. After a brief overview of the project by Tim Smith, Project Manager, about 14 people spoke on a variety of viewpoints.

Read the rest of this entry »

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San Diego files second lawsuit in groundwater dispute with Sweetwater Authority

Posted by George J Janczyn on December 21, 2010

The City of San Diego’s ongoing legal dispute over Sweetwater Authority’s project to expand groundwater pumping from the San Diego Formation aquifer has escalated with the filing of a second lawsuit.

The City’s first lawsuit, filed March 26, 2010, challenged Sweetwater’s certification of an Environmental Impact Report (EIR) and project approval (for background and a copy of that lawsuit see my October 28 report as updated December 8). The City alleged that its formally stated concerns about groundwater depletion/overdraft in the San Diego Formation, saltwater intrusion, land subsidence, brine discharge, and other issues were rejected or ignored by Sweetwater.

Subsequently, after some procedural errors in the approval process were discovered, Sweetwater Authority revisited its decision and again approved the project on November 10 (the U-T reported on that in this report).

San Diego’s newest lawsuit filed December 9 again challenges Sweetwater’s EIR certification and seeks to set aside Sweetwater’s November 10 action reaffirming project approval.

Significantly, going further, the new lawsuit also seeks the court’s declaration of San Diego’s Pueblo water rights in the San Diego Formation. Specifically, it asks:

For a declaration that the City was at the commencement of this action and now is the owner in fee simple of the prior and paramount right to the use of all the water of the San Diego Formation underlying the former Pueblo of San Diego, including all waters tributary thereto whether beneath the Pueblo or not, for the use of the City and of its inhabitants for all purposes and that Respondent Sweetwater and all other respondents have not and no one or more of them have any estate, right, title or interest in or to said waters, or any part thereof, or in the use of the same, or any right to take or use said waters, or any part thereof, save in subordination and subject to said prior and paramount right of the City.

Here is a copy of the new lawsuit:

 

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Groundwater dispute between San Diego and Sweetwater Authority

Posted by George J Janczyn on December 8, 2010

Is the City of San Diego’s environmental lawsuit against Sweetwater Authority actually more about asserting water rights in the San Diego Formation aquifer? The lawsuit alleges defects and procedural errors with the Environmental Impact Report (EIR), but a Sweetwater Authority representative told me San Diego is positioning itself to assert its pueblo water rights over the aquifer and perhaps lay claim to work already done by Sweetwater. The staffer made the remark in response to a question I asked during a recent open house at the Reynolds Groundwater Desalination Facility.

If you look at the City’s lawsuit, it does focus attention on the EIR and procedural issues — there’s no mention of pueblo water rights. However, there are definite allusions to claims on the water such as: “The City of San Diego is committed to managing its water rights and the groundwater resources within its jurisdiction…” and “…as an entity with water rights in the Formation, the City has a special interest in managing this important resource…” (page 2 of the lawsuit).

It’s true that San Diego has a “paramount right” to all water within the San Diego River watershed, including the groundwater, based on the City’s pueblo past (the Journal of San Diego History has this background on that business). The question, though, is what about the groundwater in the San Diego Formation aquifer? The issue is much murkier there.

The Sweetwater Authority has been drawing an average of 2,727 af/yr from six existing wells in the Formation since 1999, and now plans to install five additional wells to roughly double the take.

The San Diego Formation aquifer is bisected by four different drainage basins, so rights to its groundwater are hardly clear, and there’s relatively little that is known about how it behaves and is recharged. True, it has been the object of widespread study (see the USGS San Diego Hydrogeology web page and the County Water Authority’s San Diego Formation Aquifer Storage and Recovery studies). Legal claims and project ideas have been made, but the bottom line on the whole situation, as observed by Wes Danskin, Project Chief for the USGS San Diego Hydrogeology Project, is: “What I know is that the science is not well founded yet.”

Certainly any large-scale groundwater withdrawals should be based on thorough scientific understanding of the aquifer and San Diego’s lawsuit credibly addresses potential problems with increased pumping, including overdraft of the aquifer, land subsidence, seawater instrusion, and increased waste brine discharge from the desal plant going into storm drains and ultimately into San Diego Bay.

No doubt San Diego wants some of that Formation water for itself and increased withdrawal by Sweetwater threatens the remaining supply. The lawsuit states “Also, the City informed Sweetwater of a project it intends to construct within 4 to 5 years. Sweetwater chose to ignore this project as well.” For some reason the City seems reluctant to say what that is. When I sent email to PUD’s Arian Collins asking for the name of the specific project, he referred me to Eric Symons. Symons didn’t reply until a week later and then vaguely only to “confirm that it is the San Diego Formation Basin.” I’ve gotten no reply to my followup request to name the specific project.

One can try to guess which project, I suppose: here’s a general San Diego Formation Fact Sheet and a Mission Valley Basin Fact Sheet. The City also has an interest in drawing from groundwater below Balboa Park. However, the Mission Valley site is complicated by the groundwater contamination from the fuel tank farm near Qualcomm Stadium. As for beneath Balboa Park, it appears to be somewhat isolated from Formation groundwater flow so recharge would be a concern, according to Danskin.

Little is known about how the entire San Diego Formation aquifer recharges itself, but it should be safe to say the recharge capability is limited and large-scale withdrawals raise questions about sustainability.

Dec 8, 2010: A copy of San Diego’s complaint is reproduced below. Today I spoke with a clerk at Superior Court who said that Sweetwater has not yet filed a reply brief (the U-T article said today was the deadline for that), but that settlement negotiations are ongoing. A Status Conference has been scheduled for Dec 17. Meanwhile, the clerk also informed me that a NEW lawsuit will be filed on Dec 10, but it is not yet known what party will file that suit.

 

There’s another area I’ve been looking at that’s potentially linked to the San Diego Formation (it’s certainly in the San Diego River watershed), but it’s playing out a bit differently. The City has a pilot well located near the foot of the dam at El Capitan Reservoir to determine if seepage from the reservoir can be captured. Presumably that groundwater travels through El Monte Valley and is ultimately linked in some way with the San Diego Formation.

Presently many property owners in the El Monte Valley have their own wells drawing groundwater. Theoretically San Diego could exert its pueblo water rights against those wells but probably does not consider their use to be a problem.

As for the consequences of Helix Water District’s plan to develop a 5 mgd groundwater operation with its El Monte Valley IPR Project, I got this statement from Kate Breece, Public Affairs Manager at Helix Water District: The El Monte Valley Project would be a “put and take” project. We would have the right to any water we put into the basin, and we would take out no more than we put in. So, the City would not claim any of that water as belonging to the “watershed.” Our staff works with the City’s staff to make sure we keep them informed of our project.”

 

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Studying groundwater in San Diego

Posted by George J Janczyn on August 16, 2010

Drilling at Balboa Park well site

Groundwater news in San Diego doesn’t stop you cold like, say, a news report on IPR drinking water that asks “What’s the difference between the sewage used now for irrigation and the recycled sewage project the City Council approved?” (Voice of San Diego), but groundwater is an important part of San Diego’s strategy to decrease reliance on imports that are becoming less reliable & more expensive.

Presently, a comprehensive geologic and hydrologic study of the San Diego area is being done by the U.S. Geological Survey, although that work doesn’t typically lead to sensationalized news reports.

News does pop up occasionally, such as the recent revelation about what were thought to be two separate aquifers under Balboa Park and National City now seen as possibly connected — thanks to the Easter Quake in northern Baja. Or desirable groundwater in Mission Valley contaminated by MTBEs from the fuel tank farm near Qualcomm Stadium. And the Helix Water District planning to augment groundwater resources with an IPR project in El Monte Valley near El Capitan Reservoir.

Otherwise, it has been awhile since I’ve heard anything about work going on in gathering and analyzing groundwater data throughout the county, so I touched bases with Wes Danskin, the Project Chief for the USGS San Diego Hydrogeology Project to ask what’s up. Here’s what he reported:

1. We have a comprehensive data report in colleague review. It summarizes all the sw, gw, and water quality data collected as part of the study from 2001-09.

2. We will be drilling a multiple-depth well in San Pasqual in September.

3. We’d like to drill another well in the South Bay area to complete our monitoring network, and possible a well in the Chollas Creek area to close the data gaps in that area as well.

4. We are making progress on a 3-D geologic framework model of the south coastal SD County area.

5. We are synthesizing the vast amount of water quality data with the goal of understanding gw flow paths.

6. We are estimating where and how much direct recharge from precipitation has occurred over the past century over much of the county. Pretty schematic, but we hope it will be helpful in determining the major gw flow paths.

Among the possibilities raised by USGS’s studies, if we’re lucky it could turn out there’s enough groundwater beneath Balboa Park to take care of its irrigation needs and save the 1.5 million gallons per day of potable water now being consumed by the park.

 

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Update on groundwater contamination in Mission Valley

Posted by George J Janczyn on April 6, 2010

The San Diego City Council on April 5 held its first public hearing on an ordinance that would appropriate and expend $608,626.00 towards resolution of some issues relating to cleanup of groundwater contamination near Qualcomm Stadium. Quoting from the council docket:

“In 1992, an enforcement action was brought by the San Diego Regional Water Quality Control Board (RWQCB) against the party responsible for the release of petroleum products from the Mission Valley Terminal to the soil and groundwater beneath the Qualcomm Stadium site. The RWQCB ordered the discharger to clean-up the contamination by certain deadlines which are fast-approaching. That clean-up is still ongoing. The City also initiated litigation against the discharger in 2007.

The City is the owner of the Qualcomm Stadium site. The City has Pueblo Water Rights in the waters of the San Diego River, which include the groundwater basin at issue in the abovereferenced RWQCB enforcement action. The City plans to utilize this basin beginning in 2010 to pursue the groundwater objectives identified in the Long-Range Water Resources Plan, adopted by the City Council on December 9, 2002, which establishes priority elements of groundwater storage and desalination including the Mission Valley Groundwater Basin. In its efforts to advocate the City’s interests in timely meeting clean-up goals, the City retained the services of an environmental consultant and the legal services of two law firms. The funds for the consultant and legal services agreements are nearly exhausted.”

The motion on the ordinance passed without speakers or comment 7-0 (Young absent). The second public hearing and the introduction and adoption of the Ordinance will be on the Council docket of Tuesday, April 13, 2010.

April 13 update: At the second public hearing, there was no further discussion and the ordinance was unanimously approved.

Click here for supporting materials submitted to the Council.

 

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