20200615_Nat_email

Wehner, Judy
From: Wilson, Nat
Sent: Monday, June 15, 2020 1:50 PM
To: Wenner, Judy
Cc: Bauer, Michael
Subject: Re: [External] Response to Comments Sunrocks Revised Hydrogeological Report
Judy,
I don't think they need to re -do the aquifer testing, but they do need to look at their results carefully. Mark Chandler
points out a problem with the estimated radius of influence in Table 6 and the drawdowns measured in the Area 1
test. The results for OW1-1 show 56.45 feet of drawdown at 292 feet distance and the Sichardt method gives 0
drawdown at 256 feet distance (150 feet quarry depth).
That got me looking at the measured results in Table S. The data in Table 5 are not the same as what is recorded on the
hydrographs in Appendix D. Well OW1-1 shows —64 feet of drawdown on the hydrograph and is listed as 56.45 feet in
Table 5, OW1-2 shows —66 feet of drawdown on the hydrograph and is listed as 61.52 feet in Table 5. The other two
wells (OW1-3 and PW-1) are the same in the table and the hydrograph, but why does the closest well to the pumping
well (OW1-3) have the least amount of drawdown? The differences for wells OW1-1 and OW1-2 are likely due to the
recorder not being deep enough. The true drawdown needs to be calculated by using the combined tapedown data and
recorder data. But the results for OW1-3 just don't make sense. My guess is that their numbering is off and the
hydrographs are being attributed to the wrong wells. If we rearrange the wells a bit and give the well which is furthest
away from the pumping well the least amount of drawdown then then a distance drawdown analysis gives comparable
results to the Area 2 results. The OW2-2 hydrograph shows —14 feet of drawdown which is different than the drawdown
listed in Table 4 (29.6 feet). Otherwise Table 4 and the Appendix D hydrographs are in sync.
I favor using a distance drawdown analysis, because you are forced to combine the well data so you see very quickly if
there are anomalies.
I'm not concerned about the other complaints listed in Mark Chandler's document, but getting the analytical results
correct is important. These are the basis of the radius of influence calculations and the maps showing nearby wells
which may be impacted.
Let me know if you have any questions.
Nat
On Jun 8, 2020, at 9:12 AM, Wehner, Judy <iudy.wehner(@ncdenr.eov> wrote:
Fyi.
From: Mark Chandler <mchandler803Pvahoo.com>
Sent: Sunday, June 07, 2020 12:38 PM
To: Wehner, Judy <][e-mail]>
Cc: Mark Chandler <mchandler803(@vahoo.com>; IesliezimmermanlCalamail.com
Subject: [External] Response to Comments Sunrocks Revised Hydrogeological Report