Abstract
Understanding future land-use related water demand is important for
planners and resource managers in identifying potential shortages and
crafting mitigation strategies. This is especially the case for regions
dependent on limited local groundwater supplies. For the groundwater
dependent Central Coast of California, we developed two scenarios of
future land use and water demand based on sampling from a historic land
change record: a business-as-usual scenario (BAU; 1992–2016) and a
recent-modern scenario (RM; 2002–2016). We modeled the scenarios in the
stochastic, empirically based, spatially explicit LUCAS
state-and-transition simulation model at a high resolution (270-m) for
the years 2001-2100 across 10 Monte Carlo simulations, applying current
land zoning restrictions. Under the BAU scenario, regional water demand
increased by an estimated ~ 222.7 Mm by 2100, driven by
the continuation of perennial cropland expansion as well as higher than
modern urbanization rates. Since 2000, mandates have been in place
restricting new development unless adequate water resources could be
identified. Despite these restrictions, water demand dramatically
increased in the RM scenario by 310.6 Mm by century’s end, driven by the
projected continuation of dramatic orchard and vineyard expansion
trends. Overall, increased perennial cropland leads to a near doubling
to tripling perennial water demand by 2100. Our scenario projections can
provide water managers and policy makers with information on diverging
land use and water use futures based on observed land change and water
use trends, helping better inform land and resource management
decisions.