20051457 Ver 1_USGS streamflow and ground-water conditions in NC through Monday July 25.msg_20110726

Strickland, Bev
From:
John C Weaver Dcweaver @usgs.gov]
Sent:
Tuesday, July 26, 2011 11:55 AM
To:
Yonts, Woody
Cc:
Ashley. E.Hatchell @usace. army. miI; brian.cullen @noaa.gov; Haines, Brian; Lane, David; Owen, Debra;
eric.seymour @noaa.gov; gagalleh @duke- energy.comI garry_grabow @ncsu.edu;
george.mathews @noaa.gov; Brady, Harold M.; Kritzer, Jamie; jcweaver @usgs.gov;
Jeff.Orrock @noaa.gov; Prevette, Jim; Hoffmann, Jucilene; Lara.Pagano @noaa.gov; Peele, Linwood;
Michael .A.Young @saw02.usace. army. miI; michael.moneypenny @noaa.gov; Orbon, Mike; Sarwar,
Neelufa; Patricia. Tanner @noaa.gov; Peter. Corrigan @noaa.gov; richard.neuherz @noaa.gov;
rwall @ncem.org; ryan_boyles @ncsu.edu; Young, Sarah; todd.hamill @noaa.gov; Fransen, Tom; Reeder,
Tom; tony_dorn @nass.usda.gov; Lawrence, Torey; Cox, Vernon N; Munden, Wayne; Yonts, Woody;
Brian Fuchs; Allison.Wash @va.usda.gov; Kathleen Carroll; Darin Figurskey; Glenn Carrin
Subject:
USGS streamflow and ground -water conditions in NC through Monday, July 25
NC Drought advisory group,
I will not be on today's drought call due to a commitment away from the office.
Rainfall during the past week was mostly spotty across the state with a widespread pattern of "have and have -not" in
terms of precipitation occurrence. Up through Monday afternoon, a good part of the state received less than 0.5 inch
rainfall during the week (http:/ /www.nc - climate.ncsu.edu /mpe departure /). A storm system moving across the state on
Monday afternoon dropped some decent totals across the southeast Piedmont, Sand Hills, and northern Coastal Plain
region (http: / /nmg.ou.edu /).
The big weather story during the past week was the consecutive days of 100+ degree high temperatures across the state.
Lots of evaporation occurring these days under these kinds of conditions. As mentioned during last week's face -to -face
NCDMAC meeting in Williamston, the daily evaporation rates are on the order of about 0.25 to 0.3 inch per day. This
corresponds to 9 inches equivalent rainfall being evaporated during a 30 -day period, an amount that exceeds the monthly
average precipitation for most locations in North Carolina.
Streamflow conditions noted on the current real -time maps
(http:Hwaterwatch.usgs.gov/ new / ?m= real &r =nc &w= real %2Cmap) depict continued below - normal conditions across most
of the Coastal Plain. Streamflows at many USGS streamgages in this region are depicted in the "less than 10th
percentile" range with about half -dozen sites with streamflows indicated at record low for the current calendar day.
In the Piedmont and mountains regions, streamflow conditions are a mix with normal and below - normal conditions with
the more widespread normal conditions in the mountains region. Above - normal flows are currently depicted for some of
the streamgages in the upper French Broad and Pigeon River basins. Streamflow conditions in the "less than 10th
percentile" range are noted in the Broad and South Fork Catawba basins where the D1 drought category has been in
effect for several weeks.
As of July 24 (Sunday), streamflow conditions indicate 70 percent of sites across North Carolina have percentiles for 7-
day average flows falling below the 25th percentile for the calendar date (see graph below). This percentage indicates
declines in overall streamflow relative to 52 percent just a week ago.
Among the 10 Blue Ridge and Piedmont observations wells in the Climate Response Network
(http: / /ogw01.er.usgs.gov /crn /StateMaps /NC.html), water levels are depicted in the normal range for 8 wells and much
below normal for 2 wells at Chapel Hill in Orange County
(http: // qroundwaterwatch .usgs.gov /AWLSites.asp ?S= 355522079043001 &ncd =crn) and near Marston in Scotland County
(http: // qroundwaterwatch .usgs.gov /AWLSites.asp ?S= 345812079313401 &ncd =crn).
As noted last week, water levels for the 6 wells in the Coastal Plain are below normal for 2 wells, much below normal 1
well, and record low for July at 3 wells. These three wells are:
Comfort in Jones County (http: // qroundwaterwatch .usgs.gov /AWLSites.asp ?S= 345809077301408 &ncd =crn)

Hoke in Washington County (http: // groundwaterwatch .usgs.gov /AWLSites.asp ?S= 354418076463601 &ncd =crn)
Elizabeth City in Pasquotank County (http: // groundwaterwatch .usgs.gov /AWLSites.asp ?S= 361829076163201 &ncd =crn)
Draft 1 for this week's release was available as of Monday afternoon with no changes yet indicated for North Carolina.
Changes made for last week's USDM release included some smoothing of the D2 and D3 boundaries in the central and
southern Coastal Plain as well as a return of DO and D1 in the upper Cape Fear and Neuse River basins.
Based on the change in median percentiles for 7 -day average flows (see screenshot below), overall streamflow conditions
declined across much of the state during the past week with spotty occurrence of rainfall. The most widespread rainfall
occurrence was across the southeast Piedmont, Sand Hills, and northern Coastal Plain region. The percent of normal
precipitation for 30 to 60 days indicates a fairly large area of near and above normal precipitation across parts of the
central Piedmont (Yadkin River basin, Triad region).
I would suggest the group consider expanding the D1 across parts of the Broad basin to cover the South Fork Catawba
basin where "less than 10th percentile" streamflow conditions are in effect. But given the above mentioned nearby area of
normal 30 -day precipitation, the expansion probably needs to be very small, just enough to capture most of the basin.
Given the high temperatures and overall decline in streamflow, it would seem that some deterioration would be in order.
However, given the pattern of the rainfall occurrences of the past day, it is my recommendation that status quo is
probably reasonable for the remainder of the state.
Comments and opinions welcome...
Thanks.
JCWeaver
****************************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * **
J. Curtis Weaver, Hydrologist, PE
USGS North Carolina Water Science Center
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone: [phone] H Fax: [phone]
Mobile: [phone]
E -mail address -- jcweaver @usgs.gov
Internet address -- http: / /nc.water.usgs.gov/
****************************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * **
-- USDM draft (if available) --
As of Monday afternoon, draft 1 for this week's version was available with no changes yet indicated for North Carolina.
Brad Rippey, meteorologist with USDA in Washington, DC, is the USDM author for this week's release. In the email
accompanying draft 1, he made no specific comments concerning the Carolinas region.

USDM archive (you can select North Carolina from the drop -down box near the top, a quick way to see the last two USDM
releases):
htto:H drouaht.unl.edu /dm /archive.html
-- Observed precipitation --
Sources of precipitation totals are available from the following:
(1) USGS rainfall totals (sorted by county) for the last 7 days at
http : / /waterdata.usgs.gov /nc /nwis /current ?tvpe = precip &group kev= county cd
(2) State Climate Office of North Carolina at http : / /www.nc - climate.ncsu.edu /mpe departure/
(3) NOAA NWS's Advanced Hydrologic Prediction Service at http: / /water.weather.gov /precip/

Image shown below pulled from the State Climate Office of North Carolina at http: / /www.nc-
climate.ncsu.edu /moe departure/

011, -41 ncsu.edu
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USGS North Carolina wat ... internal Horne - USGS NC... USGS North Carolina WSC... AHPS Precipitation Analysis
......................................................................................................
X Find: I Rippey Previous Next
Options
State Climate Office of North Carolina
Aulti-sensor Precipitation Estimates �IVIPE)
There are possible errors associated with these radar-based precipitation estimates- This product is in laeta..
Select Layers:
Precipitation:
(3, Estimate 07..
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from normal 0
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Q2 [Radar Only] Valid Period:
24hr QPE Accumulation 0712512011 13:00:00 - 0712612011 13:00:00
-- Streamflow --
Current conditions are depicted as real -time, 7 -day, 14 -day, and 28 -day flows available in the WaterWatch series of maps
at:
http://waterwatch.usgs.gov/classic/?m=real&r=nc&w=real%2Cmap

Current conditions...
Tuesday, July 26, 2011 08 :30ET
WIM
MUSIGS
Last week's conditions...
Tuesday, July 19, 2011 09 :30ET
When viewing the USGS WaterWatch streamflow information, you can hover your cursor over a site and a pop -up box
Explanation - Percentile classes
......,.
X10
Lew
1024 25-75 76 -90 >
�
............ - �: High Idol- ranked l
M N ch beds ur
- ---- ---- -�
Be lbw al P trr� al Al y g % asc.l� aD0VV,
mar €Y I r� rm l
When viewing the USGS WaterWatch streamflow information, you can hover your cursor over a site and a pop -up box

appears with various pieces of information, including the percentile for the current streamflow AND the current percentage
of mean and median for the calendar date.
Highlighting current flows (July 26 morning) at some selected gaging stations (obtained from
http : / /waterdata.usgs.gov /nc /nwis /current / ?type =flow ):
Site number
Site name (and County)
Flow Jul 19
Current
flow
(% of)
Median Jul 26
02053200
Potecasi Creek near Union (Hertford) --
2.0
cfs
0.02
cfs
See remarks
23 cfs
02106500
Black River near Tomahawk (Sampson) --
6.4
cfs
49
cfs
17%
284 cfs
02085500
Flat River at Bahama (Durham) --
4.6
cfs
29
cfs
145%
20 cfs
02096960
Haw River near Bynum (Chatham) --
109
cfs
94
cfs
27%
348 cfs
02115360
Yadkin River at Enon (Yadkin) --
1,230
cfs
2,120
cfs
123%
1,729 cfs
02152100
First Broad River near Casar (Cleveland) --
26
cfs
29
cfs
550
53 cfs
03451500
French Broad River at Asheville (Buncombe) --
963
cfs
1,730
cfs
1260
1,370 cfs
03550000
Valley River at Tomotla (Cherokee) --
80
cfs
137
cfs
1280
107 cfs
REMARKS concerning Potecasi Creek: The USGS is currently working with equipment issues at this particular site. A
discharge measurement at 1.5 cfs was made on July 20.
Focusing on the 7-day average flows...
Visit the WaterWatch pages at http: / /waterwatch.usgs.gov /classic / ?r =nc to get the most recent data for sites of interest.
Durations plots for selected individual USGS stations can be accessed at http: / /nc. water .usgs.gov /drought /duration.html
The OVERALL 7 -day average flows by HUC map
(http:Hwaterwatch.usgs.gov /classic / ?m= pa07d &r= nc &w =pa07d nwc %2Cmap) are depicted in the image below:
Monday, July 25, 2011
8

To help provide more detail by major basin, the BELOW NORMAL 7 -day average flows by HUC map
(http: / /waterwatch.usgs.gov /classic /index.php ?map type =drvw &state =nc) are depicted in the image below:
Monday, July 25, 2011
As of July 24 (Sunday), the graph of 7 -day flow percentiles shown below indicates 70 percent of sites across North
Carolina have percentiles for 7 -day average flows falling below the 25th percentile for the calendar date. And 31 percent
of sites across North Carolina are shown as having 7 -day average flows below the 10th percentile or reaching new
minimum for calendar date.
Compared to July 17 (Sunday), the current values indicate declines in overall streamflow conditions during course of the
past week, considering 52% of sites across the state were below the 25th percentile and 22% of sites were below 10th
percentile and /or reaching new minimum for the calendar date.
Below is a graph developed from the 7 -day average flow summary table available at:
http: / /waterwater.usgs.gov/ classic / ?m= pa07d &r= nc &w= paO7d %2Ctable

i
i
If i
Less than 25th percentile Percentage of sites in North Carolina with 7 -day t
Less than 10th percentile indicated percentile range or lowe
New min forthe day
F+ September + 1 = t= t
2010 2010 2010 2010 i 2011 2011
Date
Another measure of the streamflow conditions is available from maps of median percentiles for 7 -day average flows for
the previous 7 -, 14- 30 -, 60 -, and 90 -day periods updated through July 25 (Monday). These maps are intended to
provide some kind of "long- term" index of the streamflow conditions (not available through the USGS WaterWatch pages)
that is mapped according to the classification scheme for streamflow used by the U.S. Drought Monitor. Map images (via
the above URL) showing the median percentiles for 7 -day average flows for previous 7 and 30 days are shown below.
http: / /nc. water. usgs .gov /drought/dm- streamflow.html
10

R
0
Previous 7 days
Monday, July 25, 2011
,50
Previous 30 days
Monday, July 25, 2011
r k F ,,
Explanation
Unregulated
Regulated
No - No Drought ( >30 percentile)
DO - Abnormally Dry (21 to 30 percentile)
0
❑
D1 - Moderate Drought (11 to 20 percentile)
D2 - Severe Drought (6 to 10 percentile)
D3 - Extreme Drought (3 to 5 percentile)
IF
D4 - Exceptional Drought (0 to 2 percentile)
a
IM
n/d - Not determined
0
❑
11
t

The following ArcMap screenshot shows the change in the median percentiles of 7 -day average flows for 7 -day period
from last week (with last week's U.S. Drought Monitor in the background). In other words, at a given site, take last
week's median percentile and compare it to this week's median percentile. Sites in red indicate a decrease in the median
percentile from last week to this week (suggesting a decline in streamflow). Sites in blue indicate an increase in the
median percentile from last week to this week (suggesting an improvement decline in streamflow). The size of the circles
indicates the general range in percentile increase or decrease (note legend to left of the map).
File Edit View Bookmarks Insert Selection Tools Window Help
--- ____ ____ _____mmmm________
23 61 & 10 rc r + 1:3,860,938
............................................................................................................................................. ..............................' x
-!, Layers
-1 ❑Q Automated DM maps (short string)
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-- Ground Water --
Please visit the Climate Response Network page at
http: / /groundwaterwatch. usqs. gov /StateMapsNet.asp ?ncd= crn &sc =37 (map shown below) for more information on
12
10 to 25 percentile increase
5 to 10 percentile increase
0 to 5 percentile increase
0
No percentile change
0 to 5 percentile decrease
5 to 10 percentile decrease
10 to 25 percentile decrease
25 to 50 percentile decrease
Greater than 50 percentile decrease
? ;tj ,> +
xv O a Editor
Display I Source Selection)rr
Drawing El w j Anal 11 B U
-- Ground Water --
Please visit the Climate Response Network page at
http: / /groundwaterwatch. usqs. gov /StateMapsNet.asp ?ncd= crn &sc =37 (map shown below) for more information on
12

ground -water conditions at selected USGS observation wells in North Carolina.
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......ee __
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Shown below are the hydrographs at four selected wells across North Carolina... real -time page for USGS ground water
data in NC is available at http: / /waterdata.usgs.gov /nc /nwis /current ?tvpe =qw
(MOUNTAINS) NC -144 at Blantyre in Transylvania County
(http: / /waterdata.usgs.gov /nc /nwis /dv / ?site no= 351808082374302 &agency cd =USGS &referred module =sw)
13

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---- Provisional Data Subject to Revision ----
14

(WESTERN PIEDMONT) NC -193, Piedmont RS near Barber in Rowan County
(http: / /waterdata .usgs.gov /nc /nwis /dv / ?dd cd =01 72019 00003 &format =imq default &site no= 354057080362601 &set to
qscale v =0 &begin date = 20070319)
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(WESTERN PIEDMONT) NC -193, Piedmont RS near Barber in Rowan County
(http: / /waterdata .usgs.gov /nc /nwis /dv / ?dd cd =01 72019 00003 &format =imq default &site no= 354057080362601 &set to
qscale v =0 &begin date = 20070319)
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16

(EASTERN PIEDMONT) NC -126 at Chapel Hill in Orange County
( http:/ /waterdata.usgs.gov /nc /nwis /dv/ ?site no= 355522079043001 &agency cd =USGS &referred module =sw)
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(EASTERN PIEDMONT) NC -126 at Chapel Hill in Orange County
( http:/ /waterdata.usgs.gov /nc /nwis /dv/ ?site no= 355522079043001 &agency cd =USGS &referred module =sw)
17
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17

(COASTAL PLAIN) NC -160 near Simpson in Pitt County
( http:/ /waterdata.usgs.gov /nc /nwis /dv/ ?site no= 353219077153801 &agency cd =USGS &referred module =sw)
18
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( http:/ /waterdata.usgs.gov /nc /nwis /dv/ ?site no= 353219077153801 &agency cd =USGS &referred module =sw)
18

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— Lowest recorded water level prior to MY2011 (8 +97 ft Oct 23,24, 2007)
19