It took more than four decades, an environmental catastrophe, two years of negotiations, an unprecedented cooperative effort between a coalition of private conservation organizations and a state agency, and $50 million to permanently protect what a conservation group official calls an "irreplaceable" piece of native coastal Texas.

On Thursday, the Texas Parks and Wildlife Commission, meeting at Houston's Museum of Natural Science, will act on a proposal to accept the donation of the 17,351-acre Powderhorn Ranch in Calhoun County from the Texas Parks and Wildlife Foundation, The Nature Conservancy and The Conservation Fund, the three conservation groups that recently purchased it for $37.7 million from a Kentucky-based company that has owned the property since 2005.

Almost all - $34.5 million - of the purchase price comes from the Gulf Environmental Benefit Fund, a $2.5 billion fund created with money BP and Transocean agreed to pay in plea agreements following the 2010 Deepwater Horizon rig explosion and resulting oil spill. The $2.5 billion, overseen by the National Fish and Wildlife Foundation, is earmarked to fund projects benefiting natural resources of the Gulf Coast. Texas' portion of that fund totals $203.5 million.

The purchase of the property, on which the state parks and wildlife agency plans to create a state park and wildlife management area open for public use, comes after a decades-long effort to find a way to protect the tract from looming development.

Even 40 years ago, when Texas' population was half its current size and before a booming economy and the development that followed swallowed huge chunks of what remained of the state's native coastal landscape, the Powderhorn Ranch held iconic status among those looking to ensure preservation of meaningfully large pieces of that natural heritage.

Stunningly diverse

The ranch, bounded on one side by Matagorda Bay and Powderhorn Lake on another, has for decades been one of the largest remaining tracts of intact, almost wholly unaltered, coastal prairie this side of the King and Kenedy ranches in deep South Texas. Used as a cattle ranch by the Denman family who purchased it in the 1930s and sold it in 2000, the Powderhorn holds the stunningly diverse mosaic of habitats that once stretched unbroken along much of the middle coast and supported an equally diverse array of native wildlife that includes whooping cranes, bobwhite quail, white-tailed deer, Rio Grande turkey, waterfowl, songbirds and scores more.

"It has been one of those Holy Grails of coastal conservation," Carter Smith, executive director of Texas Parks and Wildlife Department, said of the 27-square-mile tract between Port Lavaca and Port O'Connor. "Every conservation group in the country knew about the Powderhorn and how unique and spectacular it was. We've all been looking at it for more than 30 years, trying to figure a way to preserve it. But none of us could afford to buy it. It's too expensive.

"These days, most coastal property of this quality isn't sold by the acre; it's sold by the square foot," he said, referring to the fragmentation of large tracts into small lots on which homes are built.

"This certainly is a case of making the most out of a very unfortunate incident all of us wish had never happened," Smith said of using money generated by legal action in the wake of the Deepwater Horizon incident to help purchase the property. "But I think everyone should take pride in the use of these funds for this acquisition."

The Powderhorn is the largest land acquisition made using the Gulf Environmental Benefit Fund and, those involved said, marks a singularly significant conservation effort because of the size, diversity and increasing rarity of landscapes such as the Powderhorn.

"The unspoiled and irreplaceable Powderhorn Ranch is now a significant property for all Texans, and a protected national treasure," Larry Selzer, CEO of The Conservation Fund that generated $10 million in private donations toward the purchase and creation of an $8 million endowment to fund the operation and management of a place he called "a critical coastal landscape of epic size and scale (now preserved) for generations to come."

Complex collaboration

Purchase of the property involved complex and innovative collaboration between all parties, participants said. Under the deal, which will total about $50 million, the National Fish and Wildlife Foundation will transfer $34.5 million over the next three years to the Texas Parks and Wildlife Foundation. The TPW Foundation, a nonprofit group that raises private money to fund Texas Parks and Wildlife Department projects, will use some of that money to repay The Nature Conservancy and The Conservation Fund the $10 million each of the nonprofit groups provided toward the purchase.

Counting the $34.5 million from the Gulf Environmental Benefit Fund, the Texas Parks and Wildlife Foundation has raised $43 million of the project's expected $50 million price tag. The Foundation will work to generate the remaining money through private donations and grants.

The Nature Conservancy will provide habitat management efforts on the property for the coming two years, working with TPWD staff.

"We'd have never gotten this deal done without this incredible public/private partnership," Smith said, noting that use of public funds for the purchase of large tracts of land for conservation purposes is increasingly difficult because of tight budgets.

The Powderhorn Ranch has "spectacular" value to wildlife and fisheries. Most of the land is prairie/savanna carpeted with native grasses such as bluestem and punctuated with thousands of mima/pimple mounds, slightly elevated areas most of which hold motts of coastal live oak. Scores of temporary and permanent freshwater wetlands sit in the prairie swales. Thick stands of large, wind-sculpted live oaks sit on ridges along the bayshore and inland. The tract has 5.5 miles of frontage on Matagorda Bay, almost 6 miles of shoreline on Powderhorn Lake and is veined by several bayous.

Thriving wildlife

That landscape is home to thriving resident populations of wildlife, including bobwhite quail, a ground-nesting species that has seen dramatic decline in numbers because of loss of grassland habitat. The wetlands attract swarms of waterfowl that winter on the Texas coast and support shorebirds and wading birds. The oak motts provide crucial habitat for migrating songbirds.

The brackish water and salt marsh along the edges of the tidally influenced waters provide necessary estuarine habitat for coastal marine species, including shrimp, redfish and blue crabs. Those crabs are the main food source for wintering whooping cranes that, over the past several years, have expanded their territories from the nearby Aransas National Wildlife Refuge and often forage on the property.

That abundance of wildlife and natural areas offers great potential to provide high-quality, low-impact outdoor recreation for Texans, Smith said. Probable public uses include kayaking, fishing, hiking, birding and public hunting.

"Its a magical place," Smith said of the Powderhorn. "And now it'll stay that way for generations of Texans."