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How
was Tempe Town Lake filled and how is it kept full?
 Tempe began filling the 220 surface-acre lake on June 2, 1999, and
declared it officially full on July 14, 1999. The City purchased
water
for the initial fill from the
Central
Arizona Project, which delivers water statewide from the surplus in
the Colorado River. This water was delivered through the
Salt
River Project canal system. Using technology, the City of Tempe has
minimized the amount of water lost to seepage. A flood levee forms an
impenetrable wall around the sides of the lake. This levee was covered
with a structural and aesthetically attractive lake edge. Underground,
a clay wall connects to bedrock underground at the west end. On the east
end, a seepage recovery system recovers almost 100 percent of the water
that seeps into the ground. Water is recaptured by 10 wells around the
eastern portion of the lake and pumped back into the lake. Eight bladders form two
inflatable
dams that contain the water on the east and west ends of the lake
and can be deflated or inflated in 45 minutes to release overflow water
or catch flood tail water. Water released during storms is replaced with
the tail waters from water released from the lakes upstream. Water
from evaporative losses will be be replaced primarily with Central
Arizona Project water and recharge water exchanges.
Why
is Rio Salado important to Tempe?
.jpg) Unlike most cities in the metropolitan
Phoenix area, Tempe does not face issues of urban sprawl; rather it has
to creatively use the land that exists within its borders. Rio Salado
reclaims over 800 acres of once undeveloped land from the flood plain, making
it possible for river land to be developed which enhances the quality of
life of Valley residents. Rio Salado provides increased
recreational
opportunities for residents, tourist attractions for visitors and
economic growth for employment and stability. The Tempe Town Lake, which
is between 800 to 1,200 feet wide and two miles long, is the closest lake available to the
largest population residing in Arizona. The scale of this project is
larger than San Diego’s Balboa Park, the San Antonio (Texas) River
Walk, the Boston Waterfront and New York City’s Central Park. The
scope of the project is a combination of all of these attractions and
more.
Who pays for Rio Salado?
Rio Salado is a cooperative effort accomplished through public and
private partnerships. The channelization of the river, completed in
early 1996, cost $40 million and was paid for by the Flood Control
District of Maricopa County and the Arizona Department of
Transportation. Construction of the Tempe Town Lake cost just less than
$45 million, $27 million of which will be absorbed by private developers
who will also assist in long-term operational and maintenance funding.
Additionally, a lake assessment fee is structured into the cost of the
land around the lake. Some City-owned property surrounding the lake will
be leased for development, creating immediate revenue. Development is
expected to generate up to $3 million annually in sales revenue to
be reinvested into the lake. State and federal grants have been used to
help fund public art features, lake trails and landscaping.
What about flooding?
Throughout the Valley's history, the Salt River has taken lives and
destroyed buildings with its deceptively strong currents (200,000 cubic
feet per second). Through channelization, these floodwaters are
contained within an 800-foot floodway, allowing for the creation of
parks and structures in areas once subject to flood damage. This channel
consists of eight-foot thick soil cement walls, combined with the lake
edge, to form a 100-year flood
lower levee and rock gabions forming a nearly 500-year flood upper levee. The
Tempe Town Lake is designed to minimally impede the flow of floodwater.
Dams at both ends of the lake can be lowered partially or be completely
deflated depending on the size of the water releases from lakes
upstream. By restricting the placement of structures within the channel,
potential damage due to flooding can be limited to minor landscape
maintenance and cleanup.
Highest recorded Salt River flows
Tempe Town Lake is built to handle floodwaters of 250,000 cubic feet per
second. The highest recorded flows in the Salt River to date are:
What
about preserving wildlife and the native environment?
.jpg) By
concentrating water in an urban lake, more people will be able to enjoy
the environment it creates. Balancing the preservation of desert plant
materials and providing park environments for people to use is critical
to Rio Salado. The desire for green public parks is being fulfilled in
larger areas conducive to picnicking, playing games and sightseeing.
Drought-tolerant plants are being used in appropriate areas (this is
known as xeriscaping). These plants are not limited to cactus: many
trees and flowering shrubs from climates similar to Tempe's are being
used to create a beautiful park environment. These plants are not native
and are selected carefully to avoid species that would impact
surrounding native landscapes. Some 80 percent of the plant species in
Rio Salado are native. A 13-acre
Mesquite Bosque, maintained by
volunteers, has been planted at the northeast end of Rio Salado
providing refuge for wildlife, educational opportunities for students of
all ages and a natural tie to the history of the Salt River.
A feasibility study completed by the
United States Army Corps of Engineers identifies the possibility of
creating habitats at both the east and west ends of the project and in
the Indian Bend Wash outlet. These sites would be in the river channels
and would be designed to attract native animals back to the area and to
discourage migratory birds who might want to relocate to this area.
Papago Park is currently being revegitated with native plants after
years of scarring from cactus harvesting, four-wheel driving, horseback
riding, mountain biking and hiking. Papago Park remains the only area in
Tempe with significant saguaro and creosote growth.
Is the Tempe Town Lake a threat to aircraft safety?
Throughout the years, the City of Tempe has been a leader in
promoting aircraft safety. Like the hundreds of other airports located
on or around water, Tempe Town Lake is located about 12,000 feet beyond
the runways of Sky Harbor International Airport. While it is rare to
find flocks of migratory birds in the state of Arizona that commonly
interfere with airplanes, the City of Tempe has taken several steps to
ensure that Tempe Town Lake does not become a threat to airline safety.
In addition to following Federal Aviation Administration (FAA) rules and
regulations, the Tempe Town Lake design team took great care in ensuring
that the lake would not become an attraction for birds and other
wildlife. For example, the lake has no places for birds to nest or roost
as evidenced by the steep sloping walls and the deepness of the water.
Additionally, Rio Salado park areas have a strict policy against feeding
birds and wildlife and food and beverage vendors are restricted from
serving items that attract fowl, such as popcorn and peanuts. Special
wildlife habitat areas are planned near the lake, where birds can fly
with no threat to airline safety. The City's Wildlife Management Plan
addresses numerous issues related to the removal and relocation of birds
and other wildlife from areas that could be deemed unsafe for their
habitat. This plan also outlines the City’s ongoing commitment to
monitor the situation and make changes as necessary.
What about Transit?
In September 1996, Tempe citizens passed a transit improvement plan
which provides significantly increased transit service throughout the
city. Connections to the Rio Salado Project area include: additional
bicycle facilities and pedestrian amenities, expanded FLASH (Free Local
Area Shuttle) service and seven-day-a-week local/regional bus and
dial-a-ride service. The City also participates in major investment
studies that explore fixed guideway transit
options throughout the region. Three corridors have a potential effect
on the Rio Salado area. |
