Raleigh currently finds itself in the “worst-ever” drought, and has thus implemented Stage 2 water restrictions . Falls Lake is essentially barren and discussion has started about limiting new water connections and encouraging water conservation through means such as non-potable water systems.

The normal annual rainfall amount for Raleigh is around 42″ (there are many different published numbers out there.) Over the last 365 days, we’ve gotten 35″ of precipitation, a 17% deficit. This is a deficit level that has stayed constant for several months now.

To see how we got here, it helps to look at the rainfall totals per month of 2007.

Month	Rainfall	Normal	Variance
Jan	3.12	3.48	-10%
Feb	1.74	3.69	-53%
Mar	3.52	3.77	-7%
Apr	3.88	2.59	+50%
May	1.43	3.92	-64%
Jun	4.46	3.68	+21%
Jul	4.94	5.17	-4%
Aug	0.91	4.02	-77%
Sep	2.22	3.19	-33%
Oct	4.66	2.86	+63%
Nov	0.48	2.63	-82%
Dec	4.45	3.24	+37%
TOTAL	35.81	42.24	-15%

The first half of the year’s problems essentially came from May’s shortage. The other months cancel each other out. The second half of the year boiled down to August’s deficit. The 365-day 15% deficit is big, but not as big as other Southern cities . Atlanta was 37% below normal while Charlotte, Birmingham, and Tuscaloosa had deficits of 34%, 47%, and 54%, respectively.

Looking at a bigger picture, the 10-year window, we see that even with this deficit, Raleigh’s rainfall has been quite normal.

Year	Rainfall (avg=42″)	Variance
1998	49.71	+16%
1999	48.86	+14%
2000	39.34	-7%
2001	35.25	-19%
2002	47.15	+11%
2003	49.57	+15%
2004	47.05	+11%
2005	37.56	-12%
2006	53.69	+22%
2007	35.81	-17%
Total, Avg	443.99, 44.4	+6%

(2/18 Note: The 2007 variance of -17% is based on an average of 42″ while the first table’s year-long variance is calculated based on a 42.24″ average)

The table clearly shows that while we had two anomalous deficit years, we’ve had 6 years with more than 10% surplus rainfall. In fact, 2007 was preceded by a particularly wet year. Where was the hype machine during those years? If we were to look at a 30-year or 50-year window we’d see that variances like we are experiencing are quite normal, and that they are canceled out without much delay. In other words, it will rain. Conserve now but be patient. A comment at the weather.com article cited about stated:

This is La Nina electrics. The cold anomalies in the eastern tropical Pacific Ocean mean that displacement currents from global and regional lightning do not run along the tropics as efficiently and couple there with Walker circulations or WPAC storms . . . These currents, particularly from the American thunderstorms, are then more likely to flow to the either coupled events which are low impedance, such as a cold core storms this time of year or a tropical storms in the Atlantic during the hurricane season. These cold core storms do not produce as much rain in the north Gulf and tropical storm season conditions were more conductive just north of Venezuela this season, and that relatively speaking took away from displacement currents powering any cloud organizing electrics in the Gulf of Mexico this year. But it did bring us to cat 5s within weeks of each other. Don’t worry, the electrics conditions will be changing soon.

Reviewing the rainfall totals, though, shows that we’ve had deficits in the teens before, but why is it different this time? Our water shortage and restrictions have more to do with reservoir levels than with raw rain totals . Raleigh has experienced much growth during this 10-year period but has not increased its water capacity. We weren’t able to take advantage of the surplus years because we have a water capacity problem, not a rainfall problem. Far bigger cities are making do with much less water. Los Angeles normally gets 14.77″ of rain per year while Phoenix gets 7.66″, and Seattle gets 37.19″ of annual rainfall. We should be able to handle a 35″ rainfall year without all of the emotion and theatrics.

Help is on the way! The city of Raleigh is constructing the Dempsey Benton Water Treatment Plant and Reservoir at Lake Benson. The plant will open in 2010 and will mark a return to using Lake Benson for drinking water. A third plant is planned for the Little River area in eastern Wake County. It will be completed by 2025.

Until then, the City of Raleigh should use reasonable means to conserve water within the context of the reservoir’s status. If we have a surplus of water and are spilling it over into the Neuse, there is no logical reason that citizens should not use city water for routine property maintenance and entertainment.