NZOIA BASIN DAILY FLOOD WATCH UPDATE Flood Risk Indicators by s42gs6

VIEWS: 0 PAGES: 2

									                                            OFFICE OF THE PRESIDENT
                            MINISTRY OF STATE FOR SPECIAL PROGRAMMES
  WESTERN KENYA COMMUNITY DRIVEN DEVELOPMENT AND FLOOD MITIGATION PROJECT
                               ( WKCDD & FMP)
             FLOOD DIAGNOSTICS AND FORECASTING CENTRE (FDFC)


                   NZOIA BASIN DAILY FLOOD WATCH UPDATE
Date of Issue: 2nd November 2009                                                                               Issue No:
Validity: 2nd to 3rd November 2009                                                                           FDFC02NOV09

Summary
The rainfall forecast for the next 24 hours indicates moderate rainfall is likely to fall over
the basin while the stream flow forecasting model indicates that the water level at
Rwambwa is likely to fall to about 0.76m which is below the alert warning level. No risk of
flooding is expected within the forecast period.


Water levels at Rwambwa Bridge RGS
Date                                  Level (m)       Trend           Flood Risk Category                             KEY
Today’s Morning water level              0.86         Falling                                                  High Flood Risk
Forecast          2nd Nov. 09            0.86         Constant                                                 Moderate Flood Risk
water levels       3rd Nov. 09           0.76         Falling                                                  No Flood Risk

        Flood Risk Indicators and forecast for the Nzoia River Basin

  Section 1: Rainfall (mm) patterns and forecast

   The figure to the right shows the rainfall patterns
   on 1st November 2009. Light rainfall was re-
   ceived over the entire basin. The areal rainfall is
   0.0mm which is a decrease from the previous
   days’ 0.6mm.

   The rainfall forecast for the next 24 hours indi-
   cates the basin is likely to receive moderate rain-
   fall.

   Classification of point rainfall on the grid
   map


    Range        Category
    <5 mm        light
    5-15 mm      moderate
    > 15 mm      heavy




This Bulletin has been produced by Western Kenya Community Driven Development & Flood Mitigation Project
of Ministry of State for Special Programmes in the Office of the President in collaboration with the Kenya Mete-
orological Department (KMD)

For more information and enquiries contact the National Project Coordinator, Tel: 250645/50 email: floodwatch@westernkenya.go.ke
 Section 2: Current and Forecast Water Levels of Nzoia River near Rwambwa Bridge

A plot of observed water levels is shown in green in the chart below while the blue inverted bars represent
daily areal rainfall over the Nzoia Basin. The areal rainfall on 1st November is 0.0mm which is a decrease
from the previous days’ 0.6mm. The rainfall forecast indicates moderate rainfall is expected in the basin. It
is anticipated that the river level at Rwambwa will fall to about 0.76m in the next 24 hours. The brown line
shows the water level at the same time in 2008. The purple line in the plot shows the model forecast level at
Rwambwa river gauge station. No flooding is expected within the forecast period.




                                                                                                          FLOOD FORECAST CHART

               7.0                                                                                                                                                                                                                 0
                        0.6                                                                                                                                                    0.6             0.0
                                              1.3                  2.0                   2.6                                                              2.7                                                                      5
               6.0
                                                                                                                                    5.8
                                                                                                                                                                                                                                   10

               5.0                                                                                                                                                                                                                 15




                                                                                                                                                                                                                                        RAINFALL(MM)
                                                                                                                                                                                                                                   20
               4.0
  LEVEL (M)




                                                                                                             20.2
                                                                                                                                                                                                                                   25

               3.0
                                                                                                                                                                                                                                   30


               2.0                                                                                                                                                                                                                 35

                                                                                                                                                                                                                                   40
                                                                                                                                                                                                            0.85       0.76
               1.0
                                                                                                                                                                                                                                   45

               0.0                                                                                                                                                                                                                 50
                          24-Oct-09




                                               25-Oct-09




                                                                     26-Oct-09




                                                                                           27-Oct-09




                                                                                                                28-Oct-09




                                                                                                                                      29-Oct-09




                                                                                                                                                           30-Oct-09




                                                                                                                                                                                 31-Oct-09




                                                                                                                                                                                               1-Nov-09




                                                                                                                                                                                                            2-Nov-09




                                                                                                                                                                                                                        3-Nov-09
                                                                                                                                   DATE

                                                             RAINFALL                   FLOOD WARNING                             FORECAST                             2009            FLOOD ALERT        2008




 Notes for readers

              a) Areal Rainfall                                                                        b) Water levels
                                                                                   Descrip-                          Range                        Flood risk                                   Remark
      Range                           Category                                     tion                                                             Colour
                                                                                                                                                    codes
      <5 mm                           light                                        Flood warn-                       ≥3.5 m                                               Above this point flooding can occur de-
                                                                                   ing level                                                                              pending on strength of the dykes
      5-15 mm                         moderate                                     Alert levels                      2.8 -3.5                                             Watch—closer monitoring of level varia-
                                                                                                                     m                                                    tions
      > 15 mm                         heavy                                        No flood risk                     < 2.8 m                                              Safe




 This Bulletin has been produced by Western Kenya Community Driven Development & Flood Mitigation Project
 of Ministry of State for Special Programmes in the Office of the President in collaboration with the Kenya Mete-
 orological Department (KMD).

              For more information and enquiries contact the National Project Coordinator, Tel: 250645/50 email: floodwatch@westernkenya.go.ke

 Disclaimers
         1.           WKCDD&FMP does not claim authority on any boundaries in the used maps.
         2.           While extreme care is exercised in accuracy in data collection, analysis and interpretation, users should seek authority for further intended uses of the information.

								
To top