Table 2.

Projected Costs for Current and Future Adapted Stormwater Management Approaches

Location	Climate Scenario	Stormwater Management Approach	Current Cost (106 $/impervious acre)	Adaptation Cost Increase (106 $/ impervious acre)	Percent Increase in Cost
Southeast	GCM High	Conventional	0.768	0.495	64%
	GCM High	GI with Gray	1.282	0.162	13%
Arid Southwest	GCM High	Conventional	0.599	0.255	43%
	GCM High	GI Only	0.498	0.293	59%
Pacific Northwest	GCM High	GI Only	0.624	0.624	100%
Mid-Atlantic	GCM High	Conventional	0.408	0.497	122%
	Plus 10%			0.207	51%
	Plus 20%			0.374	92%
	GCM High	GI with Gray	0.396	0.538	136%
	Plus 10%			0.084	21%
	Plus 20%			0.164	41%
	GCM High	Conventional with Distributed GI	0.408	0.812	199%
	Plus 10%			0.125	30%
	Plus 20%			0.273	67%
Midwest	GCM Medium	Conventional	0.212	0.413	195%
	GCM High			0.524	248%
	Plus 10%			0.411	194%
	Plus 20%			0.766	362%
	GCM Medium	GI with Gray	0.341	0.171	50%
	GCM High			0.688	201%
	Plus 10%			0.222	65%
	Plus 20%			0.444	130%
	GCM Medium	GI Only	0.591	0.228	39%
	GCM High			0.551	93%
	Plus 10%			0.295	50%
	Plus 20%			0.598	101%
	GCM Medium	Conventional with Distributed GI	0.212	0.114	54%
	GCM High			0.355	168%
	Plus 10%			0.109	52%
	Plus 20%			0.191	90%