Bee Tree Creek Flow

Implications for water resource planning

River flow has been monitored on Bee Tree Creek since 1929.  We can use this information to support planning water usage in our area.  To start our study we can look at typical and extreme water flow for each day of the year. On our graph we look at median daily flow (green), the five percentile (red), the worst drought (dark blue), the 95 percentile (purple), and the worst floods (light blue.)

We quickly see that relative drought is normal during the summer months.  The dashed blue line shows us that typical flow on the river between late July and November is lower than worst drought conditions during March and April. 

This tells us a few things about planning.  We need to make agricultural choices that reduce water consumption during the late summer.  In this climate region, we would best choose crops that have low water demand during the summer.  We need to choose agricultural methods that reduce water consumption during the summer.  We would be wise to develop water retention methods that help soils absorb more water.   We must also be cautious not to assume that increase rain and river flow in the winter indicates the end of a drought, as late winter droughts have more river flow than normal summer flow.

On the other extreme, floods can occur any time of year.  The worst floods tend to occur in August and September, typically with hurricanes.  The time of year freest from floods appears to be April through July.  Thus, even with summer time being normally quite dry, during the summer we need to keep our flood plains ready to handle major floods. The safest time to use the flood plain would be late spring through early summer. 

To take this study a little further we can compare a drought year, 2010, to an unusually rainy year, 2005, to make some observations about being prepared for extremes.  During the summer drought of 2010 it rained only about 6 times (red arrows) in 93 days.  None of those rains were heavy soaking rains. During prime June-July growing season the region went 40 days without rain! To grow food in this climate one must be prepared to develop methods to retain as much soil moisture as possible.  One should have back-up water sources such as cisterns or rain barrels.  Remember, even though 2010 was extreme, dry conditions during the summer are normal.

2005 was an unusually wet year.  At first glance this might not be obvious as no serious floods occurred.  However, the rains were unusually persistent, as evidenced by the river flow remaining unusually high all summer. (Blue arrows show two examples of persistent rains evident in the river flow remaining high.) The persistent rains of 2005 led to fungal build up on many plants.  Most gardeners in the region lost their tomatoes to rot that summer.  Although wet summers are unusual in this region food growers must be prepared to deal with rot when crops don’t have sufficient time to dry between rains.  Molds that rot crops during a wet year may persist in the soil into the following dry year. 

Plan your gardens for dry summer growing seasons. Develop methods to retain soil moisture.  But be prepared for wet conditions.