Technical Results
Driveways
Three different types of driveway surfaces were investigated in
this portion of the study: Ecostone® concrete
block pavers, crushed
stone and traditional
asphalt. The
crushed stone driveways had the least amount of runoff over the
course of the 22 month study, with a mean of
0.04 mm. Runoff from the Ecostone® driveways was significantly
higher at 0.5 mm, and runoff from the asphalt driveways was significantly
higher than both of the other driveway types, at 1.8 mm. As would
be expected, pollutant export was highest from the asphalt driveways
(Table 1), because of the greater volume of runoff produced.
As expected, infiltration rates varied between the pervious driveways
and ashphalt driveways (Table 2).
More detail on this study can be found
in the following reference:
Gilbert, J.K., and Clausen,
J.C. 2006. Stormwater runoff quality and quantity from
asphalt, paver, and crushed stone driveways in Connecticut. Water
Research, Vol. 40, pp. 826-832.
Table 1.
Annual pollutant export from
different driveway types (kg/ha/yr).
|
Table
2. Mean (+/- s) infiltration rates from asphalt, paver and
crushed stone driveways.
|
|
Asphalt |
Paver |
Crushed
Stone |
| TSS |
230.10 |
23.10 |
9.60 |
| NO3-N |
1.78 |
1.25 |
0.15 |
| NH3-N |
0.65 |
0.12 |
0.03 |
| TKN |
13.06 |
1.08 |
0.47 |
| TP |
0.81 |
0.25 |
0.04 |
|
Test & Year |
Asphalt
(cm/hr) |
Paver
(cm/hr)
|
Crushed
Stone (cm/hr) |
| Single Ring 2002 |
0 |
11.8 ± 9.5 |
11.3 ± 3.1 |
| Single Ring 2003 |
0 |
10.5 ± 5.9 |
9.7 ± 7.8 |
| Flowing 2003 |
0 |
11.4 |
6 |
|
|
