With recent news headlines (https://abcnews.go.com/US/happen-colorado-river-system-recover-historic-drought/story?id=98475953) warning of the extreme drought conditions hitting the western U.S. and the region that makes up the Colorado River basin, cutting water use has become top of mind for many citizens and leaders in Colorado and beyond. One city in Colorado has approved a plan to cut water use in the face of this historic drought, and this plan is raising some eyebrows and generating its own headlines due to its potential impacts.
In the summer of 2022, the city council for Aurora (Colorado’s third largest city), approved restrictions on high water turf lawns for all new construction. Originally proposed by Aurora mayor Mike Coffman, all ten members of the city council voted to approve the new ordinance which limits the amount of turf lawns in new developments and golf courses. (https://www.denverpost.com/2022/08/23/aurora-limits-grass-lawns-golf-courses-water-usage/)
The ordinance prohibits water guzzling turf lawns in common areas, medians, curbside landscape and front yards. In back yards, lawns must be equal to or smaller than 45% of the area, or 500 square feet, whichever is smaller. However, an exception was included to allow front yard turf lawns for residences whose backyards are too small to fit the 45% or 500 square feet threshold.
Perhaps most importantly, the ordinance restricts turf from being used merely for decorative purposes in common areas unless it is for use in “active or programmed recreation areas.” The skinny strips of lawn often found in older commercial developments which are inefficiently irrigated as water over-sprays wastefully on to nearby walks, streets and parking lots, will hopefully become a relic of the past.
Wasting water in a parking lot.
Considering that the typical high-water lawn needs 25″ of water annually to look good and green, and Aurora (as well as most of the front-range urban corridor of Colorado) only receives 15″ of natural precipitation all year, reducing or eliminating non-active or un-programmed turf lawns is a very easy way to reduce urban and suburban water use.
This is why another recent headline grabbing story regarding reducing turf lawns was welcome news. In June 2022, the State of Colorado passed a bipartisan-sponsored measure that will encourage property owners across the state to ditch their water-wasting turf lawns (https://leg.colorado.gov/bills/hb22-1151).
The legislation is intended to use state funds ($2 million) to financially incentivize the voluntary replacement of irrigated turf with water-wise landscaping. The bill, HB22-1151, requires the Colorado water conservation board to develop a statewide program that would distribute funds to various “local governments, certain districts, Native American tribes, and nonprofit organizations” for lawn replacement programs. Those funds could then be used to pay property owners to reduce their landscape irrigation by transitioning away from high water turf lawns, towards more climate appropriate landscape treatments. The funds could also go towards expanding some existing programs that already pay property owners to replace water-thirsty lawns, about $1 to $3 per square foot of removed sod. Most of these rebates are only offered in cities in Colorado and not unincorporated areas. One goal of this legislation is to broaden this type of program to other areas in the state.
An example of a water saving landscape renovation at a multi-family property in Aurora, CO.
While $1 to $3 per square foot of removed sod may seem generous, there are reports of some landowners in California getting lawn replacement rebates up to $6/sf. (https://www.cnn.com/2022/08/19/us/california-drought-lawns/index.html). Interestingly, some of the rebate programs in California also require installation of rain barrels as well as turf lawn replacement. That is an intriguing idea for rebate offering entities in Colorado to consider, especially since rain barrels only became officially legal just a few years ago.
Researchers at Colorado State University estimate that landscapes account for at about 55% of the total annual water use for a typical single family home in Colorado.
Typical Colorado household water use; CSU extension
And most of this goes towards lawn irrigation. In the city of Denver for example, it’s estimated that nearly 25% of the city-wide entire annual water consumption is sprayed on high-water turf lawns. (https://denverite.com/2019/05/06/denverites-can-use-120-million-gallons-a-day-to-water-their-lawns/) Considering that lawns are only irrigated about half of the year or less in Colorado, that is a lot of water that could easily be saved if more lawns were changed into climate appropriate landscape treatments.
Let’s hope that the recent passage of Aurora’s lawn restriction as well as HB22-1151 helps usher in a more water conserving and water conscious future in Colorado and other states in our drought prone region. This won’t translate into a complete disappearance of high-water turf lawns. However, for the sake of our rivers, aquifers and reservoirs, it means that these water-hogging green carpets must be used wisely and judiciously in the designed landscapes of the future.
Example of beautiful low-water groundcover alternatives to high water turf lawn.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Denver Water customers received news last year that the pH of the water delivered to them by Denver Water would be adjusted from near neutral (pH 7.5) to slightly more alkaline (pH 8.5), which began in Spring 2020.
The motivating reason for this change is for improved human health, which is highly commendable (more alkaline water is less prone to leach lead from pipes into people’s drinking water; lead is toxic to human health).
But, this announcement has many in the Landscape Industry wondering what impacts this may have on irrigating landscape plants, as well as indoor plants, and how it may affect water conveyance equipment (irrigation systems, etc).
A cursory investigation via the internet seems to indicate that the possible impacts from higher pH water on irrigation systems and the plants that receive that more alkaline water are:
Increased mineral deposits on irrigation equipment as well as pots, planters, etc. For drip emitters this can be very problematic as the water emits at such a low and slow rate that calcium scale build-up could end up clogging the emitters.
Reduced absorption of minerals and nutrients by the plants.
Most of the soil pH in Colorado’s Front Range are alkaline, so it is possible that this increase in pH will have little or no effect on plants that are already suited or adapted to the native soils of our area. But for plants that don’t do well in alkaline soils, will this more alkaline water be the factor that pushes those plant over the edge? Is this such a bad thing if those plants aren’t suited for our soils (and climate) to begin with?
What are some actions you can take to mitigate the problems of more alkaline water?
Water more deeply and less often. Frequent and shallow waterings may cause more build-up of salts and minerals like calcium.
Use alkaline adapted plants in your landscape rather than plants that need acidic soils. Generally speaking, most native plants for our region (Colorado’s eastern Front Range) are well adapted to alkaline soils.
Check your irrigation equipment for hard water scale build-up. Clean or replace drip emitters that are clogged with scale to ensure proper water flow.
Add Acidifying materials to the soil, like granules available from garden stores? Some experts seem skeptical of this method, saying it is very difficult to have much impact on the total alkalinity of our native soils.
Add more organic matter such as compost? Aside from most xeric adapted plants as well as plants native to our region, many of the standard landscape plants benefit from added compost for multiple reasons. Adding compost to soil can lower the pH (more acidic) as well as aid in water retention, soil texture and provide nutrients to plants.
You may wonder if softening your water via chemical means is a good option. Several experts say this is not a good way to lower the pH of the water for plants because softened water has higher salt content, which is also problematic for plant health.
Some articles sourced on the internet mention lowering the pH of the water you irrigate your houseplants with, by adding vinegar. This may work for a small watering can used on houseplants, but for landscape plants this is simply impractical. Could an in-line fertigation system be used with an acidifier such as vinegar on landscapes? We here at ODG are uncertain about this option, but it seems like an intriguing, if also risky, option.
Time will tell how our landscapes react to the increased alkalinity of our water supply. We hope the effect is minimal, because gardening in our high altitude semi-arid climate is challenging enough as is!
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Today’s photo is a recent view of a portion of one street median renovation we designed in Lakewood Colorado. We designed several landscape plans for this renovation project, consisting of many miles of existing street medians in that city, that are slated for renewal. It was an interesting and challenging project to work on, and the city staff were great to work with. We look forward to seeing how these designs grow and flourish over time!
Landscape median in Lakewood, Colorado
Before renovation photo of the same median as above, but with camera looking north.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
It seems that the fields of landscaping and gardening are
full of many timeworn statements that people like to repeat over and over. Some
of these green “rules of thumb” are tried and true, while others may
not be so true.
One landscape stereotype regarding tree growth rates that is being challenged is the old adage that “oak trees grow slowly”. I have heard and read this many times and I have repeated this mantra myself for years. But a study of urban trees in the Denver Metro area, published by the Colorado State Forest Service, got me to rethink that stereotype.
This tree study recorded the growth rates of 19 commonly
planted trees planted in public land in the Denver suburb of Westminster, for
24 years. The authors of the study measured the trunk diameters of the trees in
1992, 2000, 2008, and 2016.
The most eye-opening nugget of information in this report is
that the white oak group of trees (bur, swamp white and English oak) were the
3rd fastest growing trees in the study! They grew faster than green ash,
lindens or honeylocust trees. They even
had the same rate of recorded growth as silver maples, a species often referred
to as a “fast grower.”
Data table from the Colorado State Forest Service’s study “Growth Rates of Common Urban Trees in Westminster, Colorado”. Authors: K.A. Wood and A.M. Poulson
One important take-away from this study for me is the fact
that we should reevaluate what trees seem to be the best for planting in
challenging ecosystems such as the urban/suburban areas of the high plains
where Denver sits. It is worth quoting the State Forest Service report to
emphasize this point:
“Some tree species revealed to be fast or moderate growers in this
study have previously been viewed as slow growers, and they are often passed
over at planting time. However, equating growth rates with vigor can be
misleading, as some of the slower-growing tree types on this list can be the
most adaptable to the area (including hawthorn, hackberry and honeylocust).
Adding newly discovered fast-growing species to the planting palette and
incorporating hardy, slow-growing species will maximize the success of planting
projects and promote species diversity.”
To be clear, it is only one type of oak trees (white oaks)
that exhibited fast growth in the study sample. Red oak was also in the study
and showed slower growth. The authors note this is possibly due to the low pH
of high plains soils.
It very well could be that other types of oak trees grow
slowly too, but we don’t have data for that. Or, perhaps another study may come
along and challenge that, as well.
So, as with many “rule-of-thumb” type
statements, don’t believe it until you have seen some data to back it up.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
In 2016, the congregation of Saint Francis of Assisi
Catholic Church in Longmont, Colorado decided to expand their existing building
to better serve their growing congregation. The proposed addition to the
existing building would impact the existing landscaping, so our company was
hired to design the renovation and adjustments of the landscape around the
building.
The remodel of the building will be done in multiple phases.
So far, phase 1 of the renovations has been constructed.
The rendered landscape plan for the Saint Francis of Assisi Church.
Like many church construction projects, this one had to be
cost conscious. Due to budget constraints and various budget reviews, the
proposed plantings were adjusted several times during the planning stages to
best fit the current needs of the budget.
One particular technical challenge was the assessment and modification
of the existing irrigation system and pumps. Our irrigation specialist was
dispatched to the field multiple times to work with the Church’s maintenance
crew to puzzle out the best way to adjust and modify the existing irrigation
system. In the end, we were able to bridge the new and existing irrigation
systems into a cohesive whole.
From a planting design perspective, the client had a few key
points they wished to address: Blend new and existing plants seamlessly; create a low maintenance & low water use
landscape; and add seasonal focal points to pair with the liturgically
appropriate seasonal milestones that are critical to the Church.
Our team worked with the Church’s maintenance team to ensure
the plantings and other landscape elements would be low maintenance. Hearty and
reliable plant species were chosen for the design. We also wanted the new
plantings to blend seamlessly with the existing landscaping. In addition to
these criteria for the plants, we also ensured the plantings in the expanded
parking lot would not obscure any critical sight lines for pedestrian and
vehicle safety.
To create seasonal focal points, we considered different
plants that might be at their peak during significant seasonal holidays. One
good example of this is forsythia shrubs with their glorious yellow blooms that
appear close to Easter, a very significant holiday in the Catholic Church. Not
only are the seasonal focal points a visible manifestation of seasonally
significant biblical events, these planting nodes provide attractive backdrops
for photo opportunities during church sponsored events such as weddings.
Working on the landscape renovations for the Saint Francis
of Assisi Catholic Church was a wonderful experience for our design team. It was satisfying to help the Church achieve
their landscape design goals for their congregation and stay on budget.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
