They'd chosen to settle in Virginia during one of the Great Droughts that regularly visit North America. This one was a bit more rigorous than any we've known in the East ~ more like the 1930s where much of the midsection of the country turned into the Dust Bowl.
The Chesapeake Bay region had become so desolate the Spanish pulled out in 1598 ~ with some of their officers ending up in Santa Fe ~ guess their 'desert experience' in the East suited them well for resettlement in a real desert.
Noteworthy, DeSoto landed in 1541 and spent a fair amount of time crisscrossing the Mid-South and the lower midwest ~ and his diary reveals the territory was fairly devoid of trees ~ so travel was easy.
I've been thinking about the Spanish experience on the East Cast for a number of years. They didn't do a whole lot with it, although they may have had an almost secret colony in New Jersey or the Eastern Shore ~ the Jamestown colony officers refer to another place somewhere within a few days sail that had upwards of 20,000 settlers as best they could tell.
There'd been a number of pirate settlements around the Bay before the Great Powers decided to put an end to Atlantic piracy. So what happened to those people, and did Philippe I/II reward his Catholic Dutch subjects with lands in America while continuing his war against his Reformed Dutch subjects in the Dutch Republic? So many mysteries in that period, but the drought was very real ~ sometimes they occur over 70 to 80 year periods where there's little rain. This one had at least one period that overlaps Jamestown settlement where it appears to have not rained at all in Virginia for 17 years!
The only fresh water was above the Fall Line (an ancient meteor crater wall in the East Coast). With no fresh drinking water nor any way to water crops the Jamestown colonists faced a dire future ~ cannibalism wasn't out of the question ~ and this isn't news!
They were close to the coast. Couldn’t they have fished?
By the way, just how often do those droughts occur?