Table 2.

Number of lakes within HydrAP ranks by NLA survey year and by ecoregion. Sampled lakes in the NLA 2007 and 2012 surveys were ranked by potential anthropogenic hydrologic alteration on a score from zero to seven across five aggregated ecoregions in CONUS (Figure 2).

	2007						2012
HydrAP	West	Great Plains	Midwest	Apps	Coastal Plains	Total	West	Great Plains	Midwest	Apps	Coastal Plains	Total
0	28	10	25	8	3	74	44	10	11	17	1	83
1	38	11	28	12	1	90	32	7	38	15	7	99
2	18	23	67	15	16	139	18	29	87	18	23	175
3	4	1	20	8	5	38	13	2	15	4	2	36
4	8	17	44	23	9	101	13	14	49	16	17	109
5	37	21	23	42	21	144	31	7	16	24	15	93
6	55	35	26	39	10	165	48	23	11	33	9	124
7	33	44	21	39	19	156	39	43	32	31	23	168
Ranked	221	162	254	186	84	907	238	135	259	158	97	887
Not ranked	17	31	29	27	17	121	25	31	36	30	29	151
TOTAL	238	193	283	213	101	1028	263	166	295	188	126	1038