Question: The community that contains Downtown Summerlin occupies how many acres?

Context:
Downtown Summerlin (shopping center)
Downtown Summerlin shopping center, initially developed as The Shops at Summerlin Centre, is an outdoor business, entertainment, fashion and retail district that is part of a mixed-use development Downtown Summerlin within the affluent community of Summerlin, Nevada.
 The center provides about 1600000 sqft of retail and 200000 sqft of business space.
Downtown Summerlin
Downtown Summerlin is the name for a 400 acre area in the center of Summerlin.
 The area is bounded by Sahara Avenue to the south, CC 215 to the west, Charleston Boulevard on the north and Town Center Drive to the east.
 Downtown Summerlin includes the like named shopping center, One Summerlin a Class A office tower, the Red Rock Casino and additional commercial buildings.
Summerlin, Nevada
Summerlin is an affluent planned community in the Las Vegas Valley of Nevada.
 It lies at the edge of the Spring Mountains and Red Rock Canyon, on the western periphery of Las Vegas, Nevada in unincorporated Clark County.
 The community occupies 22,500 acres and includes a variety of land uses, including: residential, commercial, recreational, educational, medical, open space, and cultural.
 At the 2010 census, Summerlin's population was nearly 100,000, having risen from 59,000 in 2000.
Red Rock Casino, Resort &amp; Spa
Red Rock Resort is a hotel and casino.
 It is owned and operated by Station Casinos on 70 acre located in Downtown Summerlin in the village of Summerlin Centre in Summerlin, Nevada.
 Located on Charleston Boulevard, at the interchange of Clark County 215 and some distance from the Las Vegas Strip, the resort is known as a locals casino.
 It is the flagship property of Station Casinos and the company's corporate headquarters is located on the property.
2011 Souris River flood
The 2011 Souris River flood was greater than the hundred-year flooding event for the Souris.
 The US Army Corps of Engineers estimated the flood to have a recurrence interval between 200 and 500 years.
 The Souris River is a tributary of the Assiniboine River, which it meets near Treesbank, Manitoba.
 The Assiniboine meets the Red River of the North in Winnipeg, Manitoba.
 The flooding has affected Saskatchewan and North Dakota, and overtopped levees in Minot, North Dakota causing the evacuation of about 11,000 residents.
 The flooding in Minot was worse than the 1969 flood and 1881 flood.
 Many other towns along the river were affected and many acres of farmland were inundated.
Charles Hackley
Charles Henry Hackley (January 3, 1837 – January 10, 1905), son of Joseph H. Hackley and Salina Fuller Hackley, was born in Michigan City, Indiana, on January 3, 1837.
 He was an important figure in the history of Muskegon, Michigan.
 With his father he arrived in Muskegon in 1856 from Indiana to work on the creation of the early Michigan roadways.
 Later he became the owner of many acres of cutting grounds throughout Michigan.
 Later on (with business partner Thomas Hume) he opened the Hackley-Hume Lumber Mill on Muskegon Lake in 1854.
 After many successful years the mill of operation, the mill closed in 1894, after most of Michigan's Lower Peninsula had been effectively deforested.
 While many lumber mill owners moved their operations to the Pacific Northwest, Hackley remained in Muskegon and focused on urban revitalization of that city.
Sharp Mountain Preserve, Georgia
The Preserve at Sharp Mountain (also called The Sharp Mountain Preserve) is a nature-based community located near Jasper, Georgia in Pickens County.
 It is one of three mountain communities in Pickens County, and the only one dedicated to maintaining its natural amenities.
 There are 12 mi of paved roads running through the community, but the population density is intentionally low (approximately 300 lots over 1600 acre ranging in size from a minimum of 3 acre to a maximum of 37 acres.)
 The Preserve at Sharp Mountain was named the "Best Community for Outdoor Lovers" by Pinnacle Living magazine, Unlike many planned communities, the Preserve at Sharp Mountain does not have swimming pools and tennis courts with club houses or golf courses.
 Instead, the Preserve at Sharp Mountain offers many acres of green space, hiking and nature trails, a nature pavilion, waterfalls, a bird sanctuary, a butterfly garden and various nature parks.
 The community is gated to restrict use of its 12 mi of privately owned roads to those living in the community.
 The Preserve at Sharp Mountain was developed by Four Seasons originally, which later became Naterra Land.
 Naterra's stated goal in all of its projects is "to better connect people with nature."
 Naterra Land sold out all of its inventory in the Preserve, and control of the community is now governed by a Property Owners' Association (POA).
 In 2011, the Preserve Association switched from being an HOA (Home Owners' Association) to being a POA (Property Owners' Association), each being viewed differently under Georgia law.
 In 2008 the Preserve became a recognized member of the national Firewise communities program and is one of the 13 in Georgia.
Grassland degradation
Grassland degradation, also called vegetation or steppe degradation is a biotic disturbance in which grass struggles to grow or can no longer exist on a piece of land due to causes such as overgrazing, burrowing of small mammals, and climate change.
 Since the 1970s, it has been noticed to affects plains and plateaus of alpine meadows or grasslands, most notably being in the Philippines and in the Tibetan and Inner Mongolian region of China where 2460 km of grassland is degraded each year.
 Across the globe it is estimated that 23% of the land is degraded.
 It takes years and sometimes even decades, depending on what is happening to that piece of land, for a grassland to become degraded.
 The process is slow and gradual but at the same time so is restoring degraded grassland.
 Initially only patches of grass appear to die and appear brown in nature; but the degradation process, if not addressed, can spread to decimate many acres of land, which in the most severe cases is merely bare, black soil bereft of any usefulness.
 As a result, the frequency of landslides and dust storms increases; the degraded land’s less fertile ground cannot yield any produce nor can animals graze in these fields any longer; a dramatic decrease in plant diversity in this ecosystem; and more carbon and nitrogen are released into the atmosphere.
 These results can have serious effects on humans such as displacing herders from their community; a decrease in vegetables, fruit, and meat that are regularly acquired from these fields; and a catalyzing effect on global warming.
Wasque
Wasque ("way-squee") or Wasque Beach is a 200 acre nature reserve on Chappaquiddick Island, Martha's Vineyard, Massachusetts.
 The site was established as a reservation for the public in 1967 and is one of five conservation areas on "the Vineyard" managed by the Trustees of Reservations.
 Wasque contains a sandy strand the "Boston Globe" calls "a magnificent beach." "
Travel + Leisure" named Wasque Beach the number one beach in New England and WHDH-TV reports "It's pristine, serene, and rain or shine, it's a beach-goers' delight."
 Off the shore of Wasque Beach is Katama Bay, "a vast and pristine salt water bay that includes many acres of productive shellfish beds."
Camp Meeker, California
Camp Meeker is an unincorporated community, Sonoma County, United States, located on the Bohemian Highway, between Occidental and Monte Rio.
 It has approximately 350 homes on properties ranging from a couple thousand square feet to many acres, some flat and sunny, some on steep narrow gauge railroad type one-way streets.
 The population hovers around 425.

Answer: 22,500 acres