Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

To improve flood-frequency estimates at rural streams in Mississippi, annual exceedance probability (AEP) flows at gaged streams in Mississippi and regional-regression equations, used to estimate annual exceedance probability flows for ungaged streams in Mississippi, were developed by using current geospatial data, additional statistical methods, and annual peak-flow data through the 2013 water year. The regional-regression equations were derived from statistical analyses of peak-flow data, basin characteristics associated with 281 streamgages, the generalized skew from Bulletin 17B (Interagency Advisory Committee on Water Data, 1982), and a newly developed study-specific skew for select four-digit hydrologic unit code (HUC4) watersheds in Mississippi. Four flood regions were identified based on residuals from the regional-regression analyses. No analysis was conducted for streams in the Mississippi Alluvial Plain flood region because of a lack of long-term streamflow data and poorly defined basin characteristics. Flood regions containing sites with similar basin and climatic characteristics yielded better regional-regression equations with lower error percentages. The generalized least squares method was used to develop the final regression models for each flood region for annual exceedance probability flows. The peak-flow statistics were estimated by fitting a log-Pearson type III distribution to records of annual peak flows and then applying two additional statistical methods: (1) the expected moments algorithm to help describe uncertainty in annual peak flows and to better represent missing and historical record; and (2) the generalized multiple Grubbs-Beck test to screen out potentially influential low outliers and to better fit the upper end of the peak-flow distribution. Standard errors of prediction of the generalized least-squares models ranged from 28 to 46 percent. Pseudo coefficients of determination of the models ranged from 91 to 96 percent. Flood Region A, located in north-central Mississippi, contained 27 streamgages with drainage areas that ranged from 1.41 to 612 square miles. The 1% annual exceedance probability had a standard error of prediction of 31 percent which was lower than the prediction errors in Flood Regions B and C.

Flood Extents (Post-Processed)

To improve flood-frequency estimates at rural streams in Mississippi, annual exceedance probability (AEP) flows at gaged streams in Mississippi and regional-regression equations, used to estimate annual exceedance probability flows for ungaged streams in Mississippi, were developed by using current geospatial data, additional statistical methods, and annual peak-flow data through the 2013 water year. The regional-regression equations were derived from statistical analyses of peak-flow data, basin characteristics associated with 281 streamgages, the generalized skew from Bulletin 17B (Interagency Advisory Committee on Water Data, 1982), and a newly developed study-specific skew for select four-digit hydrologic unit code (HUC4) watersheds in Mississippi. Four flood regions were identified based on residuals from the regional-regression analyses. No analysis was conducted for streams in the Mississippi Alluvial Plain flood region because of a lack of long-term streamflow data and poorly defined basin characteristics. Flood regions containing sites with similar basin and climatic characteristics yielded better regional-regression equations with lower error percentages. The generalized least squares method was used to develop the final regression models for each flood region for annual exceedance probability flows. The peak-flow statistics were estimated by fitting a log-Pearson type III distribution to records of annual peak flows and then applying two additional statistical methods: (1) the expected moments algorithm to help describe uncertainty in annual peak flows and to better represent missing and historical record; and (2) the generalized multiple Grubbs-Beck test to screen out potentially influential low outliers and to better fit the upper end of the peak-flow distribution. Standard errors of prediction of the generalized least-squares models ranged from 28 to 46 percent. Pseudo coefficients of determination of the models ranged from 91 to 96 percent. Flood Region C, located in the southwest corner of Mississippi, contained 120 streamgages with drainage areas that ranged from 0.05 to 1,010 square miles. The 1% annual exceedance probability had a standard error of prediction of 41 percent.

To improve flood-frequency estimates at rural streams in Mississippi, annual exceedance probability (AEP) flows at gaged streams in Mississippi and regional-regression equations, used to estimate annual exceedance probability flows for ungaged streams in Mississippi, were developed by using current geospatial data, additional statistical methods, and annual peak-flow data through the 2013 water year. The regional-regression equations were derived from statistical analyses of peak-flow data, basin characteristics associated with 281 streamgages, the generalized skew from Bulletin 17B (Interagency Advisory Committee on Water Data, 1982), and a newly developed study-specific skew for select four-digit hydrologic unit code (HUC4) watersheds in Mississippi. Four flood regions were identified based on residuals from the regional-regression analyses. No analysis was conducted for streams in the Mississippi Alluvial Plain flood region because of a lack of long-term streamflow data and poorly defined basin characteristics. Flood regions containing sites with similar basin and climatic characteristics yielded better regional-regression equations with lower error percentages. The generalized least squares method was used to develop the final regression models for each flood region for annual exceedance probability flows. The peak-flow statistics were estimated by fitting a log-Pearson type III distribution to records of annual peak flows and then applying two additional statistical methods: (1) the expected moments algorithm to help describe uncertainty in annual peak flows and to better represent missing and historical record; and (2) the generalized multiple Grubbs-Beck test to screen out potentially influential low outliers and to better fit the upper end of the peak-flow distribution. Standard errors of prediction of the generalized least-squares models ranged from 28 to 46 percent. Pseudo coefficients of determination of the models ranged from 91 to 96 percent. Flood Region C, located in the southwest corner of Mississippi, contained 120 streamgages with drainage areas that ranged from 0.05 to 1,010 square miles. The 1% annual exceedance probability had a standard error of prediction of 41 percent.

Data from 2012 Flood Study

Flood Contours; Flood Extents; Flood Hazard; Flood Hydraulic Categories; Flood Levels.