The PVC mat penetration device, Well A3A at Sta. A3, located just north of circle of papyrus east of the ponds restoration site at Na Pohaku o Hauwahine. The vegetation in this area is dominated by para grass and a large, circular patch of papyrus is located close by. Cattails are scattered about. Well A3 is hidden in the grasses just to the right of Well A3A.

The following legend applies to the graph above:
Vertical lines "I" and "II" mark changes in the water level measurement device: before I - two measurements of water or slurry thickness made at this station in April and June during augering and penetration device installation; I - first measuring tape device used (3 measurements); II - final tape device (see photo at right) with modified weight used. Vertical line III marks the point that a second well (A3A) was installed approximately 3 ft. away (see Discussion, below). Blue line is height of water above the "solid" bottom; the thin blue line representing converted values from measurements made at Well 2. The green line represents "top of mat" calculated from tape reading from solid bottom to pipe lip. The dashed brown line represents the boundary between a darker, root zone, and deeper muck based upon a single measurement. It is assumed that this layer does not change in thickness, although this may not be a correct, still requiring further investigation.
Sta. GPS:
Date installed:
Re-installed:
Pipe length:
Ext. above mat:
Mat thickness:
Under mat:
June 2002
Oct. 12, 2002
2.44 ft.
0.98 ft.
0.55 ft.
mud
DISCUSSION Station A3 is in an area generally similar to Station A2, but further out into the marsh. This is an area of the marsh possibly near the boundary between the "wet meadow" and floating mat. However, it is uncertain if the mat here separates from the underlying mud layer when water level rises. Initially, this location showed a considerable depth of water (over 3 ft). However, this was suspicious given other considerations. A second penetration, Well A3A, was installed nearby, revealing the bogus nature of the measurements being taken at Well A3. Apparently, the first well was accidentally installed over the geological bore hole. Measurements from Well A3 were recovered (transferred to represent the new well) by monitoring the water level in both wells for a period of time to establishing an average conversion value.

In this area, the marsh sediment consists of an upper organic or O horizon with conspicuous root developoment and a lower, clay horizon. The new well was established just before the rainfall of Oct. 15-17 which delivered over 2 in of rain at Na Pohaku o Hauwahine and effected a water level rise of 0.46 ft in the ponds. Measurements at Station A3 suggest that a rise in water level after rainfall input is not accompanied by a rise in the surface of the mat and to date there is no evidence of a layer of water beneath this station. However, a short distance further out, the vegetation mat lies on an extremely plastic layer (see Well A5).

The change in water level represented by measurements made between July 31 and October 12, 2002 (dry season WL decline) was -0.010 ft/day (-3.0 mm/day).

[START OF SECTION: Transects] | [PREVIOUS Station: A2] | [NEXT Station: A5 ]| [Site Map]
[KO`OLAU NET] | [AHUPUA`A]