HomeMy WebLinkAboutHydro Logic for Source Water Protection Plan SWPPCITY OF MERIDIAN
33 EAST IDAHO
MERIDIAN, ID 83642
CONTRACT CHANGE ORDER
Change Order No.: 1
Project Number: 781
Date: 4/12/2010
Effective Date:
CONTRACTOR: Hydro Logic
PROJECT: Source Water Protection Plan (SWPP)
The Contractor is hereby directed to make the following changes from the Contract Documents and
Plans.
Desciption:
1. Consulting fees over the original task order amount due to significantly more coordination and rework
efforts than was originally anticipated.
2. Develop a groundwater model for Meridian using an existing model developed for the West Boise area.
Bring Meridian data into the existing model, run several iterations of the model, confirm reasonable output,
and produce a technical memorandum showing the results.
3. Work with IDEA to obtain their acceptance of key concepts before reworking the SWPP.
4. After IDEA buy-in, reorganize the SWPP for submittal and certification.
Reason for Change Order:
After significant efforts to update our Source Water Protection Plan to achieve state certification, we have
come to the realization that certiification will only be attainable if we either submit to a flawed model that over
states the vulnerability of our water sources, or devlop our own model. This Change Order is to develop a
model and perform other tasks to acheive state certification of our SWPP.
Attachments:
Consultant's scope of work.
CHANGE IN CONTRACT PRICE: CHANGE IN CONTRACT TIMES:
Original Contract Price: $20,201.00 Original Contract Completion Date:
Ori final Contract Com letion Da s:
Net changes from previous C.O.'s.: Net Days change form previous C.O.'s:
No. 0 to 0 No. 0 to 0
Contract Price Prior to this C.O.: Contract Completion Date before this C.O.:
$20,201.00
Net Increase (decrease) of this C.O.: Net Days Increase (decrease) of this C.O.:
$30,000.00
Contract Price with all Approved C.O.'s: Contract Completion Date with all Approved C.O.'s:
$50,201.00
RECOMMENDED: (CONSTRUCTION MANAGE ACCEPTED (C NTRACTOR)
1--- -~ ~
~ 2 /
/
`
Date: y/3 /O Date:
APPROVED: (CITY PUR H A
/ COUNCIL APPROVAL
~ l
w
By: Keith Watts ~ ~;~ .~'~
~jvq~'~,,
Date: al - 2 3 -1 b Date. Y ~~~ ~ z~~ ~ C~' ~ rF ';
VED: (CITY)
`'~
~
4G
~- ATTEST:
n
~
~
T1
y
I -
By: ayor Tammy de Weerd By: City Clerk, Jaycee an M
~
Date: a7 2.C 1 ~ Date: - ~-] - 1 ,~°'
O
'~, \ \,..
Page 1 of 2
^ Kyle Radek
From: Ed Squires [ed~hydrolagicinc.net]
Sent: Thursday, April 01, 2010 6:01 PM
To: Kyle Radek
Subject: 4-1-2010 Meridian SWPP Change Order Request
~-
1402 W. Franklin St. Boise, 1I) 83702 {208) 342-8369 Fax {208) 342-3100 Cell• {208) 631-6781
Kyle,
I am finally able to get back to you with a proposed scope of work and strategy far obtaining short-term
state certification of the City's SWPP. As we have discussed, the "nick point" is where the City does not
have a numerical computer model with which to predict capture zone analysis for contaminant time-of-
travel {TOT) predictions and mapping. The IDEA uses a simplistic 2-D model that in no way applies to
the City's aquifer system. What is needed is a 3-D model capable of considering multiple layers and
multiple wells pumping at the same time. A third obstacle is that the DEQ staff charged with reviewing the
SWPP does not have sufficient scientific understanding to portray our analyses to the technical folks that
can understand it at IDEA (this is why they believe the best individuals to develop the City's SWPP are
the pump operators}. I have developed a proposed strategy that attempts to accomplish several goals so
that we are sure to achieve some success na matter where this_goes. Here is how I suggest we handle
this.
As I have indicated, we have already developed athree-dimensional numerical ground water model for a
large part of the Treasure Valley including Meridian. The existing made) focuses in detail on the west
Boise/Eagle area but still has a realistic framework for Meridian in terms of aquifer layers, transmissivity,
!"'~ storativity, etc. This model is far advanced to any existing computer model in existence for the Treasure
Valley, particularly because it has realistic portrayal of the dipping aquifer, aquifer layers, canal and river
leakage, domestic wells, land use, etc AND it is currently calibrated to steady state and transient
conditions including three regional scale aquifer tests that the model can replicate. We already have all
the Valleys municipal wells in the model and have assigned them to layers on a gross scale. HLI teamed
with our associate Pacific Ground Water Group in Seattle to develop this model because they have
extensive, nationally recognized modeling exper#ise which, coupled with our hydrogealogic understanding
across the Valley is a formidable team. This model can be programmed to have the same level of detail
in the Meridian area, without changing the detailed calibrated sections we have, far a tang term predictive
tool at an estimated tots! cost of about $100K. However, it is the use of the existing model for an order of
magnitude less money, that I am discussing here as a means of modeling capture zones far the SWPP.
Since our last discussion at the City (with DEQ an SWPP) we have looked at our existing model {as is) for
a predictive tool that would give reasonable results that would not later be changed dramatically when the
more detailed model is completed. We considered the distance to the curren# boundaries and believe
these would not have to be modified at this time to run same simulations. What we want to see is how
"Ground Water Vistas" ,the output software far the MODFLOW model, would be able #a depict the
coalescing cons of depression in a preliminary capture zone analysis. for Meridian.
Distances from the Meridian wells to the general head boundary (GH13) of the model range from around
13,000 feet to 37,000 feet. This seems pretty far -groundwater would have to travel at about 3.5 ft/d to
get from the well closest to the boundary to the boundary itself within 10 years. It seems to us that we
should be safe for the particles not reaching the GHB within 10 years, but the only way to find out is to try
it. Row spacings in this portion of the model are around 2500 feet. Column spacings are around 1250
feet. For particle tracking, these rather large cells do not present a problem for groundwater flow
directions {but this spacing would get a lot smaller in the long-term model). What we want to do is run all
the Meridian wells simultaneously, so we can get the picture of the coNective capture zones.
Here is a stepwise approach and associated cost estimate of how we would approach the preliminary
capture zone delineation. I would use a stepwise approach to make sure everything looks OK before
going to the next step:
4i212o a a
Page 2 of 2
1. Confirm that the flow directions look OK in that corner of the model. Generate model output of vertical
head differences to make sure the existing model captures vertical gradients in this area. Decide if this is
important.
2. Incorporate any changes that seem important. The most likely change is pumping rates for Meridian Wells
and we probably will want to change local aquifer properties and rerun the model. We would not likely try
to recalibrate the model to previous targets, just make the changes and look over the results to make sure
they are OK. If warranted, we could make some additional changes and tweak the model to refine the
output.
3. Run the model for the Meridian well closest to the boundary. Make sure the capture zone doesn't extend
beyond the boundary.
4. Set the model up with particles around each Meridian Well. Run the particle tracking. Export the particle
tracks and isolate each set to a given pumping well (this third task could be time consuming, given the
multiple wells and the 3D nature of the capture zones
5. Produce a short technical memorandum showing the modeling results.
6. We would then approach the IDEA technical folks with the model-generated capture zones to get buy-in up
front, before re-writing the SWPP.
7. Assuming we can get them on board (a likely scenario), we would move on to consolidating the SWPP into
a cohesive and comprehensive document for submittal.
I think this can be accomplished for about $15K, all in, if we can move through all phases with no show stoppers.
This would be in addition to what we have spent (our outstanding invoices) already (estimate about $10K) and
we would be very judicious with the funding, hoping not to need it all. If the City would like us to proceed with this,
I suggest we do a Change Order to Task Order No. 0781 in the amount of $30K.
Thank you for asking our advice and for considering HLI for this project; we greatly appreciate that. If the City
awards this work to HLI, we will ensure a useful product no matter what twists the road takes.
Ed
4/2/2010