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Ground Water in the Sierra Foothills - Panelists & Presentation
Ken
Schmidt BIO: Ken has a B.S in Geology
from Fresno State University, M.S. and Ph.D. in Hydrology from the University of
Arizona Registered
Geologist for California, Oregon and Arizona Certified
Groundwater Professional and Registered Hydrologist He
has 40 years of experience in the field of ground water.
Since 1972, he is the Principal of his own private Groundwater Quality
Consulting firm in Fresno. His
focus has been on hydrogeological investigations particularly in the Sierra
Nevada, the Middle East and Africa. He
has extensive experience in ground water investigations in both eastern Madera
and Fresno counties. FOCUS: Ÿ
Slide Presentation on pump testing
and determination of sustainability (sustainable groundwater yields) Ÿ
Will discuss process of ground
water recharge Phil
Desatoff BIO: Phil Desatoff is a graduate
of California State University Fresno and is a California Registered Geologist
and Certified Engineering Geologist. Phil's career spanning nearly 30
years included work in the areas of mineral exploration, environmental geology
and applied geophysics. For the last 15 years, Phil has been Geologist for
the County of Fresno. His responsibilities at the County include
managing the County's geology, groundwater, surface water, and mine
reclamation programs, and implementation of the County's seismic and
water-related policies and ordinances. Phil represents the County on the
San Joaquin River Task Force, San Joaquin Valley Water Coalition, Association of
Metropolitan Water Agencies, Fresno County Water Alliance, Upper Kings Basin
Advisory Panel, Westside Basin Advisory Panel, and is staff to the Fresno County
Water Advisory Committee. Phil is author of the County Groundwater
Management Plan and County Groundwater Transfer Ordinance. FOCUS: Phil’s
focus will be on well permits and ground water yield and quality analysis
requirements, ground water monitoring policies and programs for the county of
Fresno. Al
Steele BIO: Al is a Registered
Geologist and a Certified Hydrogeologist, with a Bachelors and a Masters Degree
from CSUF. He has been employed as a geologist specializing in groundwater in
Central California for the past 29 years. Thirteen of these years were with
Fresno County Land Development Division and the Resources Division. The past 16
years have been with the California Department of Water Resources, San Joaquin
District in Fresno. Al has dealt with water supply and water quality issues
throughout the Central California, including the San Joaquin Valley, Costal
areas, and the Sierra Nevada Mountains and Foothills. FOCUS:
As part of the panel
discussion, Al will focus on groundwater data, what is available, and what is
needed for adequate groundwater resource planning. He will explain what is
available from DWR, and what individuals and groups can obtain and generate for
themselves. And, he will discuss the uses for these data as it may apply
locally.
Millerton Area Watershed Coalition –
General Meeting October 8, 2003 Ground
Water in the Sierra Foothills Presentation
Denis Prosperi, Chair,
Madera County Water Oversight Committee (WOC) is the facilitator for the
presentation. Eastern Madera Water
Oversight Committee (EMWOC) was organized as a sub committee to the WOC to make
recommendations on county policy. Obviously, there is a water
problem in the mountains. What is the severity? What do we do about it? Presenters: Kenneth Schmidt, Ground
water consultant Phil Desatoff, geologist
Fresno County Al Steele, geologist, CA
Department of Water Resources (DWR) Ken Schmidt – How they look at water in
the foothills. Ground water primarily
occurs in fractures in the hard rock. The deepest wells are
generally about 1500 ft deep Many areas are finding water
800 to 900 hundred feet deep and deeper The deeper fractures are
able to stay open because they have rock particles such as decomposed rock in
them. The average well hits about two to five fractured zones. The source of
ground water is precipitation – rainfall and snowmelt. A watershed is a surface
drainage basin. A surface watershed is defined as where water originates.
Thus, hard rock wells generally draw water from specific watersheds. Looking at precipitation in
the foothills, Friant and lower foothills areas get about 14 inches per year.
Higher foothill areas get about 24 inches per year. That water either
evaporates, is used by plants, or runs off as stream flow. In the Kings River
watershed, for example, about a fifty percent of the precipitation runs off; in
a drought year it’s about thirty percent. The foothill area has much less
runoff. DWR data from an
investigation of the Madera area shows that, excluding the main rivers, runoff
is about 7,000 acre feet per year, or about an inch over the whole area. When you tap groundwater in
the foothills and mountains, you tap into water that would have otherwise
evaporated, been used by plants, or run off to the valley. Thus, every time we develop
ground water in the mountains, there is a resulting decrease in stream flow,
evaporation, or, the plant use of water. In the lower foothills,
average runoff is roughly an inch of water per year. The grass oak/woodland
vegetation uses most of the water, with very little left to develop for ground
water. In contrast, Shaver Lake has
an average of 30 inches precipitation per year. The conifer forest there uses
about 22 inches per year by Evapotranspiration. So, there is about 8 inches
runoff per year. Above tree line in the higher mountains, there is much more
water run off, as there is obviously less plant use. An important question to
consider when looking at a project: Where’s the ground water coming from? Are
we depending on water that is coming in from other undeveloped land and that may
be developed at some time in the future? There is almost no ground
water that leaves hard rock in the foothills area and mountains and flows
underground to the San Joaquin valley. Most groundwater runs off to streams, and
enters the valley on the surface, if it’s not used up in the foothills or
mountains first. Following are some
principals for pump testing of hard rock wells:
When doing pump tests it’s important to measure the flow independently
of the flow meter, because they can be inaccurate. It’s important to measure
the water levels, the pumping rate, and the recovery. At one time, Madera County
had 72 hour pump tests, but didn’t require measuring water level recovery. If you pump a well for a
day, some wells will recover to the static level quickly and others may not come
back at all. So, it is very important to measure recovery. Fresno County started with 4
hours, then 72 hour pump tests for community wells, now they sometimes require
up to thirty days. It’s important to pipe water away from the well when doing
a pump test by at least several hundred feet in order to eliminate the pumped
water entering the well during the test. At Shaver Lake, they
haven’t found deep ground water; most wells are about eighty feet deep or less
and are found in meadow areas. One well was drilled 1400 hundred feet deep and
never found water. Different areas will vary. Developing ground water is more
difficult technically than surface water. A study was done over a 3 to
4 year period in the mid 1970’s in the Shaver area to measure precipitation
and run off. In 1976 there was a drought, there was little precipitation and
this was mostly used by plants, so there was very little runoff. Water supplies in mountains
rely on recharge, as there is no large storage. You want to have recharge every
year, if possible. In the valley, we rely highly on storage. Yosemite Lakes Park (YLP) is
an example where they are needing to drill deeper and deeper. They started with
wells about 200 feet deep and are now down to 1400 feet. This is an example of
over drafting, or pumping more than can be sustained. In many areas this isn’t
happening. There is recharge that sustains the flow. It’s unusual, that YLP has
found water at almost every level they drilled to. In Shaver Lake, they
haven’t been successful drilling for deep water. If you put a dam there, you
could technically tap virtually all runoff. In contrast, when you tap water by
wells, you need to be in favorable areas. Being
in the lower part of the watershed is helpful, but you can’t always get there.
Sometimes, you need to get into lower areas to find well water, such as at
Yosemite West. Shaver area wells have to be
near streams or meadows to find water, and they are relatively shallow. A question came up of what
would happen in meadows if we pump water out of nearby wells. One slide showed that more
damage was done to meadows in construction than was ever done by pumping.
Meadows have alluvial deposits five to ten feet deep, the next layer is
weathered material. Meadow plants are using water up to 5 feet deep. In the
forested area on the edge of the meadows, the trees use ground water up to 10-15
feet deep or more. You can see a decline in
water based on plant use. Some pump tests are done
where they pump for five or ten days and let water level decline. These aren’t
very meaningful tests. In the
valley, they do a constant discharge test or constant pumping rate test. In the mountains, this
doesn’t tell us much. What is most useful in the
hard rock is a constant water level test or constant head test. With this
approach, you get the water level down to near the lowest fracture. The pumping
rate (gallons per minute) gradually drops off, and you can see a trend of how it
drops off. One out of about fifty hard
rock wells will hold their initial pumping rate. In most, such wells the pumping rate gradually falls off. If you pump wells that have
no recharge, at some point their pumping rate will go to zero. When you stop pumping, some
wells will recover, on their own before winter precipitation. In other wells,
the water level doesn’t come back until winter precipitation comes. It’s helpful to measure
water levels in wells at the end of the dry season up to early November to see
if they recover and to see how much rainfall you need before water level starts
coming up. Some wells never recover;
these are not tapped into modern day recharge. Pump tests on hard rock
wells are done when there isn’t recharge from surface, in the dry season.
Tests when water is running over the ground, such as in the winter are
much less meaningful. Unfortunately, we don’t
have long term data for the foothill areas. Al Steele – Ground water data, What is
available, What is needed for adequate planning The Shaver Lake study is
still the benchmark work for the area. Ground water in the
foothills is in fractured hard rock, not in a basin, not in an alluvium. It
occurs in fractures, sometimes deep, sometimes not. They have to be open
fractures, should be interconnected for success, and have to have recharge
source to have a sustainable water supply You don’t know really
until you drill a well and test what you have. In basin, you can have a
clear idea for the long term of how much water there is. Where you can physically put
wells and successfully tap into ground water will be part of the picture in the
foothills. In a community, it’s
helpful to map your wells and get as much information on them as possible. Keep
track of yields, recorded use of well, how long it’s been in existence, water
quality, etc. Put everything on a map - depths, yields, location. Data issues – specific
yields won’t apply to fractured rock. It’s not very useful data. It’s only
useful to the degree that you can get water up and out. What are the future needs
for community planning in the mountains? You see people coming in and developing
based on what they have. This makes it difficult to get per capita water use in
the mountains. Everyone isn’t using the same amount of water, unlike in an
urban area where everyone has similar lots and access. In the mountains, there
are many possibilities depending on your water yields. Developing a Plan for
groundwater supply, groundwater management: In the basin, it’s
possible to start to quantify the resource. In the mountains, it is much more
difficult. You may find some information on runoff. However, this in itself
isn’t useful, because you still have to be able to extract it through a well. Also, in the mountains you
usually don’t have water district entity, only county government. Currently, there is no data
available for our area. DWR measures hundreds of wells every year, but none are
in foothills and up. And even if they did, it would be isolated pieces of
information that wouldn’t be so useful. There may be some data from
water purveyors; hopefully they are measuring for their own information. They
have to have water quality tests done regularly, so they will have that data,
though it’s for community systems only. Driller’s logs, which are collected
at the time a well is drilled, go to the county and DWR. These are considered
confidential, only the owner and government entities can see it. It’s
important to have a government entity involved to assimilate this data. It is difficult to manage
water on a regional basis. Mostly, it has to be done on a well by well basis. As
homeowner, it’s important to measure your well levels monthly, especially
during the dry season, and to keep track from one year to another, in order to
make personal planning decisions. In subdivisions, it’s very
important to keep track of individual wells, for planning purposes. This is very difficult to do
on a watershed basis. Phil
Desatoff – Fresno County The Fresno county government
is a land use agency. What they decide to do with the land here impacts the
watershed. The county’s role is to
maintain roads, a judicial and social service system, a voting system, and to
regulate land use. Looking at land use, water
supply is critical. Land use decisions are looked at seriously. Shaver lake studies still
drive land use decisions in that area today. The county is looking at a
ground water overdraft problem. It has a growing population, a decrease of
surface water coming in, increased pressure for marketing and export of water
supplies, and state pressure to take over local ground water management. The
state was looking at areas of the county where there are quantity issues, people
having trouble maintaining their wells. The 1992 state bill that passed the
AB3030 plan, gave local water agencies authority to manage groundwater. The county got involved
partly to maintain local water management authority and to fill the data gaps.
In the foothills, there were no monitoring wells to speak of. Unless people live
within an organized water district, they’re alone. The focus of the county’s
groundwater management plan is to ensure unrestricted, non-export related,
private water use in the county. In 1997, the county adopted a ground water
management plan with the caveat that local agencies which had already adopted
plan under AB3030 would be left alone as long as they were in compliance.
Foothills area was covered by this groundwater management plan. In 1999 well permit fees of
approximately $350 were adopted. Before this time, permits were free. The
purpose was to provide funding for inspecting wells, making sure proper seals
were installed, to ensure wells were reliably located. Also, a groundwater
transfer ordinance was adopted – a permit requirement for exporting
groundwater out of the county, and for substitution of groundwater for surface
water transfer. A new general plan was
adopted, with urban growth directed at cities or other areas which were already
planned. No new designation of rural residential zoning. Many planners don’t
like that type of land use because it carves the land up too much. 72 water
related policies were added to the new plan under 4 major headings: Protecting
the existing water supply, conservation, anti-degradation, enhancing the local
water supply. The goal was to make sure
land use decisions were consistent with sound water use principles. Prior to making a decision
on land use, there must be an adequate water supply, and if there’s an impact
on neighbors, this has to be mitigated. The water supply has to be sustainable,
or covered by a plan that will be sustainable. This could lead to
development being curtailed in water tight areas. In the old general plan,
developers were asked to show there was water, however, a question was missing
– Is this supply sustainable long term? Water sustainability is
vital; the Board of Supervisors is supporting this focus when approving new
lots. On existing lot, the county
won’t get involved. Of 600 foothill well logs in
Fresno County in the last few months, 16 percent had yields of less than 1
gallon per minute – considered a dry hole, 14% had yields of 6-10 gallons per
minute, and 25% had yields greater than 10 gal per minute. In the Shaver lake area they
are monitoring well levels, there are some other sub divisions where they
aren’t now. The San Joaquin task force
brought Madera, Fresno and Merced counties together. For the first time, they
are all working together, on the same page, needing to protect the water supply
for this area. Tony
Ward – Eastern Madera Water Oversight Committee Other studies have been done
in the foothills. The Wawona study, done by USGS, is one example. USGS will be
publishing a supplemental to that study soon. In that study, they went
deeper on a couple wells which had good yields. They found water which was 6000
years or older. There was no Freon or spent uranium in the water, indicating it
was older than the mid 1940’s. They did carbon dating to discover the age of
the water. It’s most likely that water has not been recharging, since it lacks
those elements. Currently, re-drills in
Eastern Madera County are in excess of 700 ft, most are around 900 ft. The question is how long can
we overdraft? How do you ask a project
proponent to prove water sustainability? A discussion was held on
whether it is possible to gather enough data to estimate how much more people we
can handle in the watershed to stay sustainable. And then could we put a cap on
it? So we don’t end up like Oakhurst. Phil Desatoff comments that
yes, it is possible. The Shaver Lake study, a multi-year study, was able to
predict water availability 25 years later. It’s possible to approve a project
in phases, monitoring after each phase to see if it’s sustainable. It is possible to have
development based on monitoring. To stop developing until you can produce more
water, by drilling more wells. You have to get the water out of the ground
before you can evaluate what you have. The weathered zone works as
a temporary storage, filters effluent, from 5 ft to 50 ft depths possible. Since
water is in fractures, there may be less filtering going on. If there’s
chemical contamination, there’s very little ability to clear it up expect
through the weathered zone. Thus, it is very important to not dump contaminants
on the ground. Water storage issue: Every 4
out of 10 years there is a flood release on the San Joaquin River. It’s
possible that there will be a storage program and Oakhurst can use that water
but they would have to pay for it. There is a potential for
smaller foothill communities to fall through the cracks if they rely on
groundwater, Auberry, Prather, etc. There is not enough
information to estimate long term reliability of water in the Auberry area.
There is a need to do an assessment, look at alternative water supplies such as
storage. There is also an issue of
water storage impacting local residents. Local storage most likely will happen
at Temperance Flat; more definitive information will come out in about 6 months. Tony Ward of EMWOAC
responded by further stating that in the Oakhurst, Coarsegold area, lots of
water shortage events happening up there. How do we solve trend? Hillview water district is
an example of a significant event. They didn’t drill enough wells to keep up
with population growth, and they are not able to have quality water. They need
to find an additional 500 gallons per minute well capacity. They will move out
to the Sierra lakes area to find it. A couple wells have popped up in that same
area with very high uranium levels. Eastern Madera county
development has happened primarily through parcel maps. Most development is on
individual wells. In the Coarsegold area, there are over 6000 people clustered
in the area, pulling from wells, with surrounding lots being 2 acre
entitlements. Ahwahnee, Sierra Meadows,
Dillon Estates and others are cumulatively developing a potentially huge
problem. EMWOAC is estimating 298
gallons per day are needed for just household usage. The Miami highlands area is
exceeding that by three times. There is a big problem there
with more development being planned. The area is growing faster than we know
what we have in terms of water supply. EMWOAC broke out 6 elements
that need to be addressed. Available ground water study
AB303 – still in need of funds Plan water needs – What do
we need? Create maps for each area, particularly the Hwy 41 corridor Acquisition of water –
Where do we get it? Working with the Madera County WOC, and exchange
contractors, and while watching the price of acre feet going up. Where do we get water? There
is a need to create infrastructure. One possibility is to bring water from
Redinger Lake and deliver it to cluster areas - Coarsegold, Oakhurst, and
Ahwahnee – by piping it in through North Fork. Conservation – How do we
get water into the soil and have better percolation? Education – Central Sierra
Watershed Committee has this portion. They are producing articles on how to live
wisely with water for local newspapers. There is a need to have
parameters around development to make sure the water shortage problem doesn’t
keep happening. There are currently 25-30
thousand people living in Eastern Madera County. Based on available lots that
are currently entitled, close to 60 thousand people are projected to be in the
area in 17 years. There is an immediate need
of approximately 2000 acre feet per year to meet in ground plumbing needs. Based
on data for future build out, 10,000 acre feet per year will be needed in
future. On Rd 416, there are people
on 2 acre parcels running out of water. If their wells can’t go deeper,
they’re out of water. The probability of drilling a new well on such a small
parcel is very unlikely. Many wells need to be
drilled deeper and deeper, which shows we are in an overdraft situation. We have
a net loss situation at this point, between foothill and valley needs, and
there’s people wanting to come in to export water. A new bill was passed
recently which gives owners the right to build a second home on lots 2 acres or
greater, provided there is adequate infrastructure. This will increase future
build out. The estimated 10,000 acre ft that is projected for future water needs
doesn’t address lots of 5 acres or greater. To get our own AB3030 plan,
we will need to get Eastern Madera County on one big water system. Septic tanks are also a
serious issue, if we build out and bring in 10,000 acre ft of water, where do we
put the sewage? The next step is to look at
how to handle sewage, and to see if we can help resolve some of our water needs
by reusing water. Eastern Madera County needs
to find supplemental water. Yosemite Lakes Park was
approved in 1971 for build out based on data that the housing would be for
retirees and part-time residents. Today, they are 50 years ahead of schedule,
and the population is composed of permanent residents with big families, not
retirees as expected. |
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