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Estimated R is summarized in Table 4 and Figure 8. Equivalent annual R (365 days from June 23, 2009) ranged from 88% (MH3) to 94% (OPEN2) of total R given in Figure 8 and Table 4. The difference between maximum (MH3 – 696 mm) and minimum (OP1 – 431 mm) annual R represented ∼30% of mean annual precipitation and ∼66% of the ∼400 mm of mean annual R for the ORM's outcropping sands and gravels (Gerber & Howard 2000, 2002). Larger R for 2009–2010 relative to mean annual R partly reflects above-average study period Pg. Total R showed two distinct groupings: OPEN and MH with R from 594 to 794 mm (49–59% of Pg), and YP and OP with R from 480 to 565 mm (22–39% of Pg). MH sites produced large R (R0.2 > 3,200 mm, R0.2:Pg > 2.5) close to tree boles, well in excess of RR. The area 0.2–0.5 m from MH boles produced R0.5 > 2× that of RR and >130% of Pg, and consideration of these focusing zones increased R for MH stands by 10–18% relative to non-weighted R. Although SF focusing in RP sites enhanced near-bole R, it produced insignificant changes in total R relative to non-weighted R. Consistent inter-site differences in R in a given land cover corresponded to Pg, with OPEN1 > OPEN2, MH3 > MH1 and MH2, and OP3 > OP1 (Figure 8). Nevertheless, error bars often overlapped for R for sites in the same land cover.
Table 4

Total recharge (R) below 1 m depth, R by R zone (R0.2, R0.5 and RR) and the fraction of each relative to above-canopy precipitation (Pg) (±estimated error), and the % increase in R relative to non-weighted R

SiteTotal R (mm)Total R:PgR0.2 (mm)R0.2:PgR0.5 (mm)R0.5:PgRR (mm)RR:Pg% change in R relative to non-weighted Ra
OPEN1 634 ± 70 0.51 ± 0.06        
OPEN2 594 ± 69 0.49 ± 0.06        
MH1 625 ± 97 0.52 ± 0.08 3,245 ± 663 2.69 ± 0.53 1,587 ± 462 1.32 ± 0.38 534 ± 101 0.44 ± 0.08 14 
MH2 630 ± 88 0.52 ± 0.07 3,309 ± 653 2.75 ± 0.54 1,651 ± 489 1.37 ± 0.41 558 ± 90 0.46 ± 0.07 10 
MH3 794 ± 93 0.59 ± 0.07 3,389 ± 665 2.54 ± 0.50 1,731 ± 505 1.30 ± 0.38 655 ± 93 0.49 ± 0.07 18 
YP1 487 ± 100 0.39 ± 0.08 621 ± 107 0.50 ± 0.09   481 ± 104 0.39 ± 0.08 
YP2 480 ± 95 0.39 ± 0.08 615 ± 102 0.50 ± 0.08   475 ± 99 0.38 ± 0.08 
YP3 525 ± 81 0.42 ± 0.07 657 ± 90 0.53 ± 0.09   517 ± 86 0.42 ± 0.07 
OP1 480 ± 85 0.40 ± 0.07 579 ± 88 0.48 ± 0.07   479 ± 86 0.40 ± 0.07 
OP3 565 ± 93 0.42 ± 0.07 664 ± 96 0.50 ± 0.07   564 ± 94 0.42 ± 0.07 
SiteTotal R (mm)Total R:PgR0.2 (mm)R0.2:PgR0.5 (mm)R0.5:PgRR (mm)RR:Pg% change in R relative to non-weighted Ra
OPEN1 634 ± 70 0.51 ± 0.06        
OPEN2 594 ± 69 0.49 ± 0.06        
MH1 625 ± 97 0.52 ± 0.08 3,245 ± 663 2.69 ± 0.53 1,587 ± 462 1.32 ± 0.38 534 ± 101 0.44 ± 0.08 14 
MH2 630 ± 88 0.52 ± 0.07 3,309 ± 653 2.75 ± 0.54 1,651 ± 489 1.37 ± 0.41 558 ± 90 0.46 ± 0.07 10 
MH3 794 ± 93 0.59 ± 0.07 3,389 ± 665 2.54 ± 0.50 1,731 ± 505 1.30 ± 0.38 655 ± 93 0.49 ± 0.07 18 
YP1 487 ± 100 0.39 ± 0.08 621 ± 107 0.50 ± 0.09   481 ± 104 0.39 ± 0.08 
YP2 480 ± 95 0.39 ± 0.08 615 ± 102 0.50 ± 0.08   475 ± 99 0.38 ± 0.08 
YP3 525 ± 81 0.42 ± 0.07 657 ± 90 0.53 ± 0.09   517 ± 86 0.42 ± 0.07 
OP1 480 ± 85 0.40 ± 0.07 579 ± 88 0.48 ± 0.07   479 ± 86 0.40 ± 0.07 
OP3 565 ± 93 0.42 ± 0.07 664 ± 96 0.50 ± 0.07   564 ± 94 0.42 ± 0.07 

R0.2 and R0.5 are R in the 0.2 m and 0.5 m focusing zones, respectively, and RR is R outside of the focusing zones.

aNon-weighted R standardizes stemflow (SF) by the stand area (see text) and ignores focused throughfall (TFF), i.e., it assumes spatially uniform TF inputs.

Figure 8

Cumulative above-canopy precipitation (Pg) and recharge below 1 m depth (R, ± estimated error) for the study period: (a) OPEN, (b) MH, (c) YP and (d) OP. Vertical dotted lines demarcate study seasons: GS = growing season, F = fall, WS = winter–spring.

Figure 8

Cumulative above-canopy precipitation (Pg) and recharge below 1 m depth (R, ± estimated error) for the study period: (a) OPEN, (b) MH, (c) YP and (d) OP. Vertical dotted lines demarcate study seasons: GS = growing season, F = fall, WS = winter–spring.

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