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Parks & Recreation: Wetland Plants

The most desirable plant community for the Wetlands Park, called "emergent wetland," filters pollutants out of the valley's water supply and prevents erosion.  It has the highest value to wildlife of any possible plant mixture in the park, providing forage and cover for migrating shorebirds and waterfowl.  The Master Plan proposes to increase the present 78 acres of emergent wetland to 202 acres.  Open water will increase from one to six acres.  The Plan adds 130 acres of enhanced riparian (streamside) vegetation with Goodding willow, cottonwood, and mesquite.  Common reed will decrease from 295 acres to 278 acres.  The largest plant community, mainly occupying the toe of the alluvial fan descending from Frenchman's Mountain and Rainbow Gardens.  The waterways of the Park area are now dominated by the undesirable tamarisk monoculture.  Tamarisk will remain the dominant plant commuinity but will drop from 985 to 786 acres.  Elimination of tamarisk with chainsaw and herbicide has begun.

EMERGENT WETLAND

Cattails, river bulrush, American threesquare: offers the highest value to wildlife, cleans and retains water. 

COMMON REED

A monoculture plant which helps retain and clean water in the wash.  Less value for habitat. 

RIPARIAN

Streamside plants such as Goodding willow, cottonwood, and mesquite.  Offers wildlife habitat. 

UPLAND

Mohave Desert scrub: creosote bush, four-wing saltbush, desert holly and shadscale.  Little support to wildlife. 

TAMARISK

This monoculture (single species) plant wastes untold gallons of water through evaporation and does not help purify the water flowing through the Wash or provide wildlife habitat. 

STRAND

In the sparsely vegetated eastern part of the park, strand communities contain jimsonweed, big saltbush, Fremont cottonwood, Goodding willow, Russian thistle and cocklebur.  Offers little support to wildlife.

PLANTS:

ABSORB TOXINS, REMOVE BACTERIA

Our pollution is nutrition for plants.  reed and cattail absorb nitrogen, calcium, magnesium, phosphorus, and heavy metal salts (which are toxic to humans).  Clean water flows out of the marsh and back into our water supply.  Water teeming with bacteria as it enters the marsh is cleaned to zero bacteria by the time it leaves.  Many viruses are eliminated.  The wetlands efficiently and thorougly decontaminate runoff.  Cattail are a key to the beneficial processes of the marsh, but only a few small strands of cattail now grow in the marsh.  When the erosion control system, with dams and ponds, is complete, the cattail can come back in one season. 

PLANTS:

SLOW WATER SPEED and FORM A DENSITY CORRIDOR

When tons of wastewater flow into the dense acres of reed and cattail the water movement slows to less than two feet per second.  At that rate the water drops its sediment before it arrives at Lake Mead.  Marsh plans distribute the valley's water runoff evenly over a wide course, preventing erosion.  Slow moving, shallow water has no chance to become an eroding force.  Even floodwaters are no match for the stopping power of the marsh.  Water cools as it slowly flows for miles in the shade of reed and cattail.  The cooler water molecules are closer together, making the water denser and heavier than the warmer surface water of Lake Mead.  Wash water flows to the cool bottom layer of the lake, taking residual pollution with it, away from the Water District intake pipeline in the center layer.  

Plant Sampler