HomeMy WebLinkAbout05-01-23 Public Comment - M. Wictor - Public Comment 5_1_2023 More online RESEARCH ~ Trees DO affect Hydrology, Water Cycle, and Groundwater (1 hectare)From:Mary Wictor
To:Agenda
Cc:Nicholas Ross; Shawn Kohtz
Subject:Public Comment 5/1/2023 More online RESEARCH ~ Trees DO affect Hydrology, Water Cycle, and Groundwater(1 hectare)
Date:Monday, May 1, 2023 12:06:36 PM
Attachments:Binder-Public Comment 5-1-2023 Trees & Water.pdf
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See attached 5-page .pdf file with info as inputs.
Public Comment 5/1/2023 More online RESEARCH ~ Trees DO affect Hydrology,Water Cycle, and Groundwater
From:Mary Wictor (mwictor@yahoo.com)
To:mwictor@yahoo.com
Date:Monday, May 1, 2023 at 10:47 AM PDT
Dear City of Bozeman, please distribute to Community Development Board, City Commission, Parks, & for
App. 22264 Canyon Gate
I submitted Public Comment on 3/30/2023 providing visuals and information specific to the land and area
adjacent to Canyon Gate.
My Public Comment on 4/17/20 provided questions to ask specific to the context, land, and area for the
Canyon Gate Prelim. Plat.
In my Public Comment of 4/25/2023 I provided research and Public Hearing inputs from former MT Legislative
Rep. Mr. Kerry White who said, “I think one thing we need to look at is the amount of trees
and their consumption of water.”
Also, I had provided the 2006 Study by Dan C. Ambercrombie on how just tree thinning on 3,000 acres raised
the water table 80+ feet.
[This input stated Rep. Kerry White was to consider not just the City of Bozeman, but even wider into the
County as we grow.]
Per the City Staff response by Engineering Director Nick Ross cc: Shawn Kohtz City Engineer, he noted that
SCALE (large or small) is important--and said, "...we would welcome any and all evidence of scaled effects
that may change our understanding."
I appreciated hearing from the City directly, and provide his email response pasted below. But I did do more
research online this week and ask that you review it to learn or confirm what you may realize generally--but
apply it to the Context of the Canyon Gate land area.
I am trying to get from "No" to "Know" with regard to "Does removal of trees affect hydrology?" to help ensure
Site design & Infrastructure Planning do indeed consider the current functions of 110+ large trees that stand in
groves in the lower, natural swales on Canyon Gate.
Appreciate your time and attention looking at and reading through this information done as online research
applicable to even 1 hectare.
Mary Wictor, 1504 Boylan Rd, Bozeman, MT ... please scroll down to my several pages that summarize this
additional research.
----- Forwarded Message -----
From: Nicholas Ross <nross@bozeman.net>
To: mwictor@yahoo.com <mwictor@yahoo.com>
Cc: Shawn Kohtz <skohtz@bozeman.net>
Sent: Tuesday, April 25, 2023 at 03:05:27 PM PDT
Subject: re: Dose removal of trees affect hydrology?
Good afternoon Ms. Wictor, and thank you very much for your recent public comment. I continue to be
impressed at this community’s willingness to help!
Please note that within engineering and hydrologic processes, scale has a massive effect on outcomes.
We are very much in agreement that huge tree clearing operations on the scale of 3000 acres such as the
study you provided would very much have the potential to substantially impact groundwater.
The question we were asked, however, was the impact of a project that will be approximately 0.03% the size of
the study you cite.
If I may attempt an analogy, this is a bit like the difference in health effects from a single glass of red wine with
dinner on occasion compared to daily alcohol abuse. Very different outcomes from the same action, just at
different scales!
It’s our professional interpretation, through years of reading similar studies, that hydrologic impact on an
aquifer of the size underlying the Canyon Gate property in question would not see any significant change from
tree removal on the scale that is being proposed. Therefor, I support the accurate response given when Mayor
Andrus asked specifically about the scale of the Canyon Gate project.
We of course welcome any and all evidence of scaled effects that may change our understanding!
Take care and thank you again for your continued interest,
-Nick
Nicholas Ross, P.E.
Director | Transportation and Engineering
City of Bozeman
C: 406-595-3437
O: 406-582-2315
nross@bozeman.net
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Page 1
Dear City of Bozeman: PUBLIC COMMENT 05/01/2023 by Mary Wictor
For Community Development Board, City Commission & App. 22264 Canyon Gate
cc: Nick Ross P.E. Director Trans./Engineering, & Sean Kohtz P.E. City Engineer
https://weblink.bozeman.net/WebLink/DocView.aspx?id=274358&dbid=0&repo=BOZEM
AN&searchid=87dc3725-92b8-4db0-b573-f3f778d773e2
Link is to my, “Public Comment 4/25/2023 ~ Does removal of Trees affect hydrology?”
I had provided some of the inputs given by former MT Legislature Rep. Mr. Kerry White.
In sharing that Public Hearing info, I had hoped it would be used in-general + for 22264.
Also, 4/25/2023 I did receive an email reply from City Staff, noting SCALE is important.
Regarding, “Will removal of 110+ large trees affect groundwater to be higher?”
For this Public Comment 5/1/2023, I hope to get from a “No” to “Know”— considered.
SCALE & IMPACTS
In the 2017 Public Hearing on water (rights, wells, watersheds, & aquifers), Rep. Kerry
White (now former) had said, “I think one thing we need to look at is the amount of
trees and their consumption of water.”
[I recall also he had verbally mentioned, for example, that for farmland agricultural uses
regarding Sprinkler irrigation vs Flood irrigation, the former has higher evaporation/loss.]
On the SCALE of State of Montana, Gallatin County, or even just the City of Bozeman,
with regard to water, it may indeed be important to look at and consider the amount of
trees not only removed, but the # PLANTED and tree types in addition to where planted.
In the 11/17/2020 adopted 2020 Community Plan page 12 of 148, the City of Bozeman
current footprint is 20.9 square miles, which times 640 acres/square mile= 13,376 acres.
I read an article online, www.nature.com/scientificreports,
Ilstedt, U. et al Intermediate tree cover can maximize groundwater recharge in the seasonally dry tropics.
Sci. Rep. 6, 21930; doi: 10.1038/srep21930 (2016). Which tested an “optimum tree cover theory…”
Trees can reduce water availability but aid percolation into soils & are important for groundwater recharge
[Math: 3000 acres per Study mentioned by Rep. Kerry White, is 22.4% of the City ~ 1/4.]
Thus, in juggling water availability and consumption/use, the 2006 Dan Ambercrombie
report done in the Sacramento Mountains, New Mexico, just their 3,000 acre study area
(5 sq. mi.) of thinning trees increased the ground water level / water table by over 80ft.
In the email response to me, Director Nick Ross relates, part of Canyon Gate is only
.03% the size of that Study. So, he says effectively, “No, removing trees has no effect.”
Looking at City of Bozeman maps, Canyon Gate treed-areas are <1% of 3000 acres.
Using online measurement tools for “area,” below I calculate = about 1 hectare (1ha).
Page 2
Watering-up: Studies of Groundwater Rising After TreesCut does note:
Dubé et al. (1995) confirmed that clearcuttings, even on 1 ha [~ 2.5acres], caused rises of the water table
I offer the following for consideration. Canyon Gate Application #22264 is on about 25
acres of land. The lowest natural swales where soils have more moisture grow many
large, significant in size and function Cottonwood trees [grow in 1 hectare vs 0.9acres—
(.03x3000=0.9)] Via other Public Comment, count of these trees is 111, over 110 trees.
Even though this is a “small” area, the trees stand in fairly dense groves. From doing
more research online, Cottonwood trees can use from 50 – 200 gallons per day, each.
So, mathematically, over 110 trees x 200 gallons per day, totals 22,000 gallons per day!
[Using online City of Bozeman maps & tools, area of the Tree groves is ~ 2.5acres, and
1 ha (hectare) is ~ 2.5 acres. {It’s more than the 0.9acres figure per calculation above.}
Thus, again, I ask and wish to know, what might complete removal of all these trees,
110+ significant Cottonwood trees that each may use 50-200 gallons per day, do to the
water table, where high groundwater is already known to be at 6.44ft to 13ft depth?
Trees effect hydrology & the water cycle: Without Trees:
Intercept water via canopy/leaves/branches No Interception—rain falls onto ground
Use water, uptaking via Transpiration No Transpiration, does increase runoff
Shade plus heat is reduced by tree processes Hotter & more soil/surface evaporation
Tree litter and roots improve soil infiltration Loss of leaf litter, habitat for birds/wildlife
Increase biodiversity and carbon capture True Net loss & Climate impacts
Human Health is affected/improved by trees CDB & City Commissioner spoke to this
Page 3
BOTTOM LINE: It was hard to hear just “No” when Mayor Andrus had asked if removing
110+ trees would affect groundwater or not + I am certain Trees do help to clean water.
It is my hope in doing this further research, that TREES WILL ALWAYS be a key part of
the equation for development, and truly considered during infrastructure planning—
especially for drainage, comprehensive stormwater management, & flood prevention.
Sincerely, Mary Wictor – Bridger Creeklands Association of Neighbors (BCAN) member
1504 Boylan Rd City-approved/chartered objectives for eight (8+) neighborhoods
{In 2019-2020 I did spend 100 hours in classes & 150+hours as a Native Plant Steward}
~~~~~~~~~~~~~
Summary of info Read via Internet Browsers (Google Chrome & MS Edge) April 2023
Searched for “how deep do cottonwood tree roots go”
“relationship between removing trees and groundwater level”
Cottonwoods consume large amounts of water in their growth cycle.
[Only some of the water in a plant becomes growth, 1-10% at most.]
A single cottonwood tree can consume 50-200 gallons of water each day.
A mature cottonwood tree uses 200 gallons of water a day!
[In comparison, and oak tree can consume up to 50 gallons/day.]
Cottonwood trees are deciduous with heart-shaped leaves and roots submerged to 4-ft.
Genetically programmed to produce shallow roots (3-6ft) since they grow in floodplains--
but their taproot can extend into the earth as deep as 15 feet depending on soils, tree
age and size, if single or spaced in a grove/stand, and how far it is to the water source.
The roots are deep enough to help anchor the tree in the ground to provide stability
during high winds, and offer a windbreak plus are well-suited to areas with moisture.
They perform best in interior regions with hot summers & cold winters.
Cottonwood trees are beautiful*, native, fast-growing & adapted to thrive in floodplains.
The naturally shallow root systems have lateral roots that radiate out. When floodwaters
come, the roots get O2 needed to breathe + the tree survives when floodwaters recede.
*Cottonwoods: their shiny, waxy leaves have flat stems, so they shimmer and rustle in the wind.
The effect is eye-catching & distinctively attractive. The tree offers strong fall color, with leaves
fading to glowing shades of gold.
Life span is typically 70-100 years, but potentially 200-400 years if have a good growing
environment. The cottonwood tree is the fastest growing native tree in North America.
Cottonwood trees offer ample shade and may grow to reach 100-feet tall and wide.
Are cottonwood trees and poplar trees the same?
Botanically speaking, a cottonwood tree is a type of poplar tree.
Cottonwood belongs to the botanical genus of Populus,
which translates to a common name of poplar.