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SALTWATER INTRUSION INTO GROUNDWATER

  • 1.  SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-18-2017 07:00 PM

    I'm curious about saltwater intrusion into groundwater supplies.  What are some good locations where this is happening? And what research has been done on this?



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    Matthew Hosey EI, A.M.ASCE
    Waggoner Engineering, Inc.
    Gulfport MS
    (228)206-1115 EXT 704
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  • 2.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-19-2017 06:30 PM

    Matthew,

    This is a big problem in Florida, and there is a lot of research around it.

    I've attached a college paper I wrote on the subject a while ago - it has some good references (I think).

    Hope it helps.



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    Adrian Pearson A.M.ASCE
    Marine Engineer
    Moffatt & Nichol
    New Orleans LA
    (617)893-8488
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    Original Message


  • 3.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-19-2017 06:39 PM
    I do not have any research on this subject.  I suggest you contact the City of Oxnard, CA water department as a starting point.  Or perhaps the Fox Canyon Ground Water Management Group - probable contact is through the Ventura County, CA Public Works Agency.  Salt water intrusion has been a problem in the Oxnard plain where there is a lot of farming that uses wells and, of course, the City of Oxnard.  The ground water pumping lowered the fresh water table levels and the good old Pacific Ocean started to intrude into the area under the Oxnard Plain where the farmers and the City got water for their uses.   Hope this helps point you in the good direction.

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    William Haydon P.E., F.ASCE
    Civil Engineer
    Ventura CA
    (805) 642-0985
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    Original Message


  • 4.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-19-2017 06:47 PM
    Investigating "Henry's Problem" would be a good place to start.  The MODFLOW/SUTRA documentation would also be helpful.

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    Dustin Fredricey EIT, A.M.ASCE
    Junior Engineer/Assistant Surveyor
    Kelder Engineering
    Willits CA
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    Original Message


  • 5.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-19-2017 06:52 PM
    I would say seawater intrusion is a natural phenomenon but it is usually aggravated by human activities such as over-pumping of groundwater from coastal aquifers for irrigation purposes etc. I worked on the assessment of seawater intrusion in one of the coastal cities of East Africa at Master's level. My findings, however, show that very few parts are injuriously impacted by seawater intrusion and they are mostly regions within 500m of the Ocean.

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    Temitope Idowu S.M.ASCE
    Research Student
    Jomo Kenyatta University of Agriculture and Techno
    Nairobi
    2540718111621
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    Original Message


  • 6.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 07:26 AM
    In Texas, you can look at the water supply of El Paso.  They have two aquifers with different salinity concentartions.  One is freash water, the other brackish. Water management strategies were developed to prevent intrusion of saltwater to the freshwater.

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    Andres Salazar P.E., M.ASCE
    Principal
    Walter P Moore and Asscociates
    (832) 341-1188
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    Original Message


  • 7.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 08:19 AM
    There is not a lot of saltwater intrusion in ground water supplies due to dewatering operations during construction. Aquifers for water supplies are normally quite deep, and "normal" dewatering for subsurface construction is 30' of less.There are normally occurring saltwater aquifers that you must avoid but in SW Fla that are between 50 to 100 feet deep. In one area, the COE drilled a well in the 1950's that pierced a naturally occurring saltwater aquifer at around 100' deep. That caused a contamination of water supplies in a 10 mile radius for depths of 40' to 100'. 
    Dewatering for construction in South Florida can be detrimental to subsurface foundations though. A prolonged dewatering operation of 25' deep or more can cause sinkholes since our water tables are so close to the surface. The presence of subsurface rock formations, cause a loss of soil from openings in the rock when the water is drained from the upper layers taking soil with it.

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    Keith Dean A.M.ASCE
    President
    Stevens and Layton Inc
    Fort Myers FL
    (239)693-1400
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    Original Message


  • 8.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 08:19 AM
    Hi Matthew,

    I know this is an issue in Australia, in Perth and Adelaide.

    http://www.groundwater.com.au/media/W1siZiIsIjIwMTMvMTIvMTgvMjNfMjVfMDRfMzUxX1NXSV9maW5hbC5wZGYiXV0/SWI_final.pdf

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    Xavier Pedeux EUR ING, M.ASCE
    Project Engineer II, Wet Weather Group
    AECOM
    Cleveland OH
    216-523-2113
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    Original Message


  • 9.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 08:20 AM
    Saltwater/seawater intrusion is a huge problem in many locations around the world. In the USA, I can list first-hand involvement in this problem in such locations (going around the coastline clockwise) including: Cape Cod; Long Island NY; NJ; DE; SC/GA; FL; and SoCal.

    Because of this, a considerable amount of research has been done, as well as implemented engineering solutions, plus invoking of planning and management approaches - including forcing of such by legislative and regulatory action.

    Thus, the water resources literature has many, many contributions dealing with this problem. In particular, I recommend that you look to the National Ground Water Association (NGWA, see National Ground Water Association - National Groundwater Association) for help and resources - including not only the literature, but also for prior and future events that deal with this issue.

    And, for any ASCE EWRI leaders who are reading this blog, I suggest considering a collaboration between ASCE and NGWA in regard to educational outreach and future events. I would be happy to facilitate such a connection - in my role as an ASCE/BSCES member as well as currently serving on the Board of Directors of NGWA.

    Best Regards,

    Bob Schreiber

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    Robert Schreiber P.E., D.WRE, M.ASCE
    Vice President
    Newton MA
    (617) 332-2847
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    Original Message


  • 10.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 08:20 AM
    Check Cedar Key Florida....

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    Jason Gowland P.E., M.ASCE
    Senior Engineer
    GSE Engineering
    Williston FL
    (352) 486-1197
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    Original Message


  • 11.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 09:31 AM
    Hi Matthew,

    NYC has experienced this phenomenon going back to the early 1900s due to industrial and residential growth with pumping levels peaking in the 1920s-1930s.  The New York State Water Conservation Law enacted in the 1930s caused a gradual reduction in groundwater extraction from industrial sources but saltwater intrusion is still present due to continual pumping from well fields needed to keep the subways dry.    Since NYC no longer gets its drinking water from the ground it's largely under the radar.

    I was involved in a feasibility study several years back looking at different ways to beneficially reuse the brackish groundwater pumped instead of discharging it to the rivers/bays.  It never moved past the feasibility stage due to re-prioritizing after Superstorm Sandy.  I worked with Bernice Rosenzweig and William Solecki of Hunter College who may have completed some research on the topic.

    Best,
    Robert

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    Robert Fields P.E., M.ASCE
    New York NY
    (646) 438-1661
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    Original Message


  • 12.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 11:41 AM
    The Los Angeles Basin has extensive experience with seawater intrusion with plenty of research and studies.  LA has a lot of experience with the construction and operation of seawater barriers to protect groundwater supplies from seawater intrusion, too.  Here's a good launching point to start from on the subject:

    Water Resources Seawater Barriers Page



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    Michael Wegley P.E., M.ASCE
    CA
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    Original Message


  • 13.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 01:54 PM
    Looks like you already have plenty of examples, but I'll add my previous location (Monterey County, CA) to the mix. This is a big issue for a region that's short on surface water and has minimal GW recharge.

    http://www.mcwra.co.monterey.ca.us/seawater_intrusion_monitoring/seawater_intrusion_maps.php


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    Nicholas Hayden Aff.M.ASCE
    Montgomery Associates
    Cottage Grove WI
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    Original Message


  • 14.  RE: SALTWATER INTRUSION INTO GROUNDWATER

    Posted 01-20-2017 02:50 PM
    Hi Matthew

    I'll add our issues on salt water intrusion in south Florida as well. Salt Water intrusion is a very big issue in the State of Florida, and one that much research has been done and is continued to be done. Here at Miami-Dade County Water and Sewer Department, we work with the US Geological Survey and our own Miami-Dade County Department of Environmental Resources Management to monitor the salt intrusion front in the Biscayne aquifer here in MD County, and are continually adding new monitoring stations as the front either has moved or where we have data gaps in the monitoring network.  Here are some links to USGS publications and websites for our salt front monitoring program - https://pubs.er.usgs.gov/publication/sir20145025 ;

    data: https://www.sflorida.er.usgs.gov/sal_data/index.html

     We are in the process of updating the salt front for publication with the USGS, however our monitoring system is very robust and probably one of the most sophisticated in the world. We have integrated many different types of data (water quality, isotopes,  geophysical logging, surface seismics, etc) into monitoring the salt front here. If anyone is interested in our monitoring network and data, we would be very happy to discuss and share.

     We have a very strong groundwater modeling program here at Miami-Dade County, and work with the USGS and the South Florida Water Management District on modeling the salt front and how it will affect water resources here in south Florida. The model documentation and initial results can be found here:

    https://pubs.usgs.gov/sir/2014/5162/

     We are also working with other counties in Southeast Florida through the Southeast Florida County Compact, as this is a regional issue, and not just a Miami-Dade County issue. The Compact has developed a Unified Sea Level Rise Projections for the region, and we are continuing to model using the Unified projections to assess salt front advancement in relation to SLR and climate change, and how we will need to respond as a utility to those changes.

    Link to Compact site: http://www.southeastfloridaclimatecompact.org/

     In addition, Florida Department of Environmental Protection has put together a Salinity Network Workgroup for the State which includes FDEP, USGS, and many other agencies and utilities – Contact Rick Copeland, P.G. Ph.D.

    Environmental Consultant

    Florida Department of Environmental Protection

    2600 Blair Stone Rd. 

    Tallahassee, FL.  32399-2400

    (W) 850-245-8503

    (C) 850- 559-7199

    Link to 2016 SNW report: https://fldeploc.dep.state.fl.us/appdata/status/SolZ/Q_meetings/march2016/07-salinity-network-wkgp-03302016.pdf

     
    Hope this helps - if you would like more information please contact  either myself or:

    Virginia Walsh, P.G., Ph.D.

    email: walshv@...
    Senior Professional Geologist
    Chief Hydrogeology Section
    Miami-Dade Water and Sewer Department


     



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    Bertha Goldenberg P.E., M.ASCE
    Assistant Director
    Miami-Dade Water & Sewer Dept
    Miami FL
    (786)552-8120
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    Original Message


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