Prepared in cooperation with the Florida Department of Transportation
Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Scientific Investigations Report 2011–5034
U.S. Department of the Interior U.S. Geological Survey Front cover:
Large photograph: USGS hydrographer Mark Stephens measuring streamflow over the road at Withlacoochee River near Pinetta, Florida, using acoustic Doppler current profiler during the flood of April 2009. Photograph by Erik Ohlson, USGS, April 8, 2009.
Small photograph: USGS hydrographer Erik Ohlson measuring streamflow through a culvert on Highway 90 at the Suwannee River at Ellaville, Florida, gage during the flood of April 2009. Photograph by Rachel Pawlitz, USGS, April 11, 2009. Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
By Richard J. Verdi and Joann F. Dixon
Prepared in cooperation with the Florida Department of Transportation
Scientific Investigations Report 2011–5034
U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director
U.S. Geological Survey, Reston, Virginia: 2011
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Suggested citation: Verdi, R.J., and Dixon, J.F., 2011, Magnitude and Frequency of Floods for Rural Streams in Florida, 2006: U.S. Geological Survey Scientific Investigations Report 2011–5034, 69 p., 1 pl.
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Contents
Abstract...... 1 Introduction...... 1 Purpose and Scope...... 1 Previous Studies...... 1 Description of Study Area...... 2 Data Compilation...... 4 Annual Peak Flows...... 4 Basin Characteristics...... 4 Estimation of Flood Magnitude and Frequency at Gaged Stations...... 5 Log-Pearson Type III Flood-Frequency Analysis...... 6 Skew Coefficient...... 6 Regional Flood-Frequency Regression Analysis...... 7 Generalized Least-Squares Regression Analysis...... 7 Accuracy and Limitations of Flood-Frequency Estimates...... 8 Weighting of Log-Pearson Type III and Regression Analyses...... 10 Estimation of Flood Magnitude and Frequency at Ungaged Stations...... 12 Sites on Streams that Cross Flood Region or State Boundaries...... 13 Comparison with Previous Analyses...... 13 Effects of Flood Distribution and Magnitude in the Peak-Flow Dataset...... 14 Flood-Frequency Analysis for Large Streams...... 15 Apalachicola River...... 16 Suwannee River...... 17 Summary...... 19 Acknowledgments...... 19 References Cited...... 19 Appendix 1. Flood-frequency estimates using PeakFQ version 5.2 for Regions 1–4...... 22 Appendix 2. Variance of prediction values for gaging stations used in Florida regional regression analyses...... 58 Appendix 3. Flood-frequency estimates using PeakFQ version 5.2...... 69
Plate
1. Locations of hydrologic flood regions and gaging stations in Florida...... back pocket
Figures
1. Map showing the location of the study area and ecoregions in Florida...... 3 2–4. Graphs showing— 2. Distribution of drainage area and storage for the four hydrologic regions in Florida.....10 iv
3. Relation of flood streamflow to drainage area for selected streamgaging stations and P-percent chance exceedance for the Apalachicola River in Florida...... 16 4. Relation of flood streamflow to drainage area for selected streamgaging stations and P-percent chance exceedance for the Suwannee River in Florida...... 17
Tables
1. Basin characteristics considered for use in the regional regression analysis...... 5 2. T-year recurrence intervals with corresponding annual exceedance probabilities and P-percent chance exceedance for flood-frequency discharge estimates...... 6 3. Regression equations for geographic regions in Florida...... 9 4. Valid ranges of basin characteristics for the regional regression equations...... 10 5. Comparison of Bulletin 17B flood-discharge estimates from this investigation with Bulletin 17 or Bulletin 17A estimates from previous investigations...... 12 6. Comparison of regression equation flood-discharge estimates from this investigation with regression equation flood-discharge estimates from previous investigations...... 13 7. Comparison of weighted flood-discharge estimates from this investigation with weighted estimates from previous investigations...... 14 8. Comparison of weighted flood-discharge estimates from this investigation with weighted estimates from the Bridges (1982) investigation...... 15
v
Conversion Factors and Datums
Inch/Pound to SI Multiply By To obtain Length inch 2.54 centimeter (cm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area square mile (mi2) 2.590 square kilometer (km2) Flow rate cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) Hydraulic gradient foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)
Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C = (°F – 32) / 1.8 Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Elevation, as used in this report, refers to distance above the vertical datum.
Abbreviations and Acronyms
DEM Digital Elevation Models GIS Geographic Information System GLS generalized least squares NED National Elevation Dataset NHD National Hydrography Dataset QA/QC quality assurance and quality control R2 root mean square error, coefficient of determination USGS U.S. Geological Survey
Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
By Richard J. Verdi and Joann F. Dixon
Abstract Purpose and Scope
Methods for estimating the magnitude of floods for The purpose of this report is to update previously selected percent chance exceedance probabilities are published flood-frequency information for Florida by provid- presented for ungaged streams in Florida that are not sub ing methods for estimating the magnitude and frequency of stantially affected by regulation, channelization, or urban floods at ungaged streams. The report also presents frequency development. Flood-frequency flows also are presented for estimates of peak flow using data collected through Septem- 275 Florida streamgages used in the regional regression analy- ber 2006 at streamgages. This report includes: (1) regional sis. Regression relations used generalized least-squares regres- equations for estimating the magnitude and frequency of peak sion techniques to estimate flood magnitude and frequency flows on rural ungaged streams in Florida; (2) estimates of the on ungaged streams as a function of basin drainage area and a magnitude of floods at the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and storage factor. These regression equations were developed for 0.2-percent chance exceedance levels for 305 streamgages in four different hydrologic regions in Florida. The flood regions Florida, Georgia, and Alabama; (3) techniques used to develop were delineated based on plotted residuals, previous flood- regression equations to estimate the magnitude of floods on frequency studies, and geologic, physiographic, and drainage- rural ungaged sites in Florida; (4) the accuracy and limitations area maps. The methods used in this report are based on flood- of these equations; (5) example applications of the methods; frequency characteristics for 305 streamgages including 275 in and (6) comparisons of the data and results in this report with Florida and 30 in the adjacent states of Georgia and Alabama, previously published studies. all having at least 10 years of record through September 2006. For the larger streams outside the limits of the regression Previous Studies equations—the Apalachicola River and Suwannee River at Ellaville and below—the report includes graphical relations of This report supersedes previous USGS reports estimating peak flow to drainage area. the magnitude and frequency of flooding in Florida. Earlier USGS studies describing flood-frequency relations throughout the State include reports completed by Pride (1958), Barnes Introduction and Golden (1966), Rabon (1971), Seijo and others (1979), Bridges (1982), Giese and Franklin (1996), and Hammett and DelCharco (2005). Most of the general organization, content, Engineers rely on flood-frequency statistics to aid in the equations, and explanatory material contained within this design and location of bridges, culverts, embankments, dams, Florida report are consistent with the discussions and language and other structures near streams and rivers. These data are used for three similar reports from Alabama (Hedgecock and required for flood-insurance rates and for flood-plain manage- Feaster, 2007), Georgia (Gotvald and others, 2009), and South ment (Hedgecock and Feaster, 2007). Carolina (Feaster and others, 2009). Data and additional The Florida Department of Transportation needs accurate discussion unique to the magnitude and frequency of floods in flood-frequency information to efficiently design bridges and Florida have been inserted where applicable with the original drainage structures in Florida. To meet this need, the U.S. USGS report sources accredited or shown as “modified from.” Geological Survey (USGS), in cooperation with the Florida Pride (1958) conducted a study estimating and regionaliz- Department of Transportation, conducted a study to update ing floods in Florida using peak-flow data through 1953 based previous flood-frequency estimates given in several reports on calendar year from 146 streamgages. Flood-frequency based on peak-flow data collected through September 2006 relations for the 146 streamgages were defined by graphical from streamgages (modified from Hedgecock and Feaster, means. The State was divided into two flood regions based on 2007). 2 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 geometric similarities in flood-frequency graphs. Composite Bridges’ (1982) analysis used guidelines presented in U.S. frequency curves were developed for both regions that defined Water Resources Council (1977) Bulletin 17A. Multiple- ratios to determine recurrence intervals up to the 2-percent regression analysis was used to develop equations for three chance exceedance probability (50-year flood) based on the geographic regions for Florida. Three basin characteristics mean annual flood for that station. Pride (1958) recognized within Regions A and C were determined to be statistically that flood-water storage in lakes and marshes could substan- significant in describing the variability in flood flows: (1) tially lower flood magnitudes at some locations; thus, Pride’s contributing drainage area, (2) channel slope, and (3) the study included a method for adjusting flood magnitudes by percentage of drainage area covered by lakes. Two basin accounting for attenuation resulting from flood-water storage characteristics were determined to be statistically significant in drainage areas upstream from selected streamgages. in describing the variability in flood flows for Region B: (1) Barnes and Golden (1966) analyzed flood-frequency contributing drainage area and (2) the percentage of drainage relations throughout the United States based on peak flows area covered by lakes. The average standard error of estimate for each water year (October 1 through September 30) for the regional equations as developed by Bridges (1982) was through 1961. The evaluation included streamgages from all 56 percent. of Florida, and parts of Mississippi, Alabama, and Georgia. Giese and Franklin (1996) updated the flood-frequency There were 132 streamgages in Florida used in this analy- relations for 32 streamgages in the boundaries of the Suwan- sis, and each streamgage had 5 or more years of record. The nee River Water Management District using period-of-record method and technique employed by Barnes and Golden (1966) annual peak flows through water year 1994. Their analysis fol- was similar to the one used by Pride (1958) and is commonly lowed guidelines presented in U.S. Water Resources Council referred to as the index-flood method (Dalrymple, 1960). (1982) Bulletin 17B to generate log-Pearson Type III distribu- Barnes and Golden (1966) subdivided the southern Atlantic tion curves for each gage. The assumption was made that the and eastern Gulf of Mexico States into four hydrologic flood regional regression equation for area of study in the District regions. Florida was included in all four regions. Flood flows was the same as presented in report by Bridges (1982). The for up to the 2-percent chance exceedance probability (50-year average standard error of estimate of the regional equation for flood) were determined, as well as methodology for reduc- this region as developed by Bridges (1982) and used by Giese ing flood flows for drainage areas where lakes and swamps and Franklin (1996) was 62 percent. provide water storage. Hammett and DelCharco’s (2005) investigation Rabon (1971) made the first attempt to use evaluated annual peak flows from 94 streamgages in west- multiple-regression analysis as a way to regionalize flood- central Florida; 75 of the streamgages were within the frequency relations in Florida. Rabon’s investigation used boundaries of the Southwest Florida Water Management 145 streamgages throughout the State with a variety of flow District and the remaining 19 were along the border. Data for characteristics, such as average and low flows and each had each streamgage consisted of at least 10 years of record and a minimum of 10 years of record. The annual peak flows for included period-of-record annual peak flows through water the period of record up to water year 1970 for each gage were year 2001. Similar to the Giese and Franklin (1996) study, mathematically fitted to a log-Pearson Type III distribution Hammett and DelCharco (2005) followed guidelines presented curve as a means to estimate magnitudes and frequencies in U.S. Water Resources Council (1982) Bulletin 17B in their of floods up to the 2-percent chance exceedance probability analysis to generate log-Pearson Type III distribution curves (50-year flood). Rabon subdivided Florida into two hydrologic for each station. Additionally, they used multiple-regression flood regions. analysis to develop equations for four regions in west-central Seijo and others (1979) evaluated peak flows from Florida. Three basin characteristics were determined to be 64 streamgages throughout west-central Florida using the statistically significant in describing the variability in flood guidelines set forth by the U.S. Water Resources Council flows throughout regions 2, 3, and 4 in west-central Florida: (1976) in Bulletin 17. A Pearson Type III distribution curve (1) contributing drainage area, (2) channel slope, and (3) was fitted to the logarithms of annual peak-flow data for the the percentage of drainage area covered by lakes. Two basin period of record through 1976 for each streamgage. West- characteristics that were statistically significant in describing central Florida was subdivided into three flood regions, and the variability in flood flows throughout Region 1 are: (1) flood-frequency equations were developed for each region contributing drainage area, and (2) the percentage of drainage using multiple regression analysis. Seijo and others (1979) area covered by lakes. The average standard error of predic- reported the average standard error of estimate of the regional tion for the regional equations as developed by Hammett and equations was 43.5 percent. DelCharco (2005) was 58 percent. Bridges (1982) evaluated annual peak-flow data for the period of record through water year 1978 for each of the 182 streamgages considered throughout Florida. Of the 182 Description of Study Area streamgages evaluated, 159 were long-term streamgages with This study included all of Florida and covered an area 10 to 53 years of record and the remaining 23 streamgages of approximately 58,560 square miles (mi2) within three U.S. were rainfall-runoff streamgages with 7 to 17 years of record. Introduction 3
Environmental Protection Agency level III ecoregions— thousands of lakes and ponds, more than 50 river systems, Southeastern Plains, Southern Coastal Plain, and Southern 33 first magnitude springs (flow greater than 100 cubic feet Florida Coastal Plain (fig. 1; Griffith and others, 2008). The per second (ft3/s), more than any other state), and numerous ecoregions in Florida represent areas of general similarity in bays and estuaries. The St. Johns River is the longest river ecosystems and in the type, quality, and quantity of environ- in Florida, measuring 273 miles (mi) in length. Water bod- mental resources. Additionally, these ecoregions provide a ies comprise 4,424 mi2 of the 58,560 mi2 total area of Florida spatial framework for research, assessment, management, and (Florida Office of Cultural and Historical Programs, [undated], monitoring of ecosystems and their components. The rela- accessed August 30, 2005, at http://dhr.dos.state.fl.us/facts/ tively flat topography of Florida ranges from sea level to the stats/quick/). Replenishment of the water bodies occur in highest known natural point of 345 feet (ft) at Britton Hill near multiple ways, but most often from rainfall runoff. Other Paxton (Walton County in northwest Florida, fig. 1). Hills and replenishment sources are flow from the upward movement rolling hills are the predominant features in the panhandle and of groundwater springflow into surface streams, including northern parts of the State, whereas the swamps and wetlands some that originate in Georgia or Alabama. Water loss occurs of the Everglades prevail in the south (Pride and Crooks, through evaporation, transpiration, water use, and flow into 1962). The wide range of water bodies in Florida include the Gulf of Mexico or the Atlantic Ocean (Pride and Crooks, 1962).
Britton Hill 65g Tallahassee 65f 65p 75j 65f 75g 65p 65p 65h Jacksonville 75i 75a 75i 75a 65f 65f 75e 75f 65o 75i 75a 75i 75a 75k 75i 75l 75k 75k Gainesville 75k EXPLANATION 75c Southeastern Plains 75l 65f Southern Pine Plains and Hills 65g Dougherty Plain 65h Tifton Upland Orlando 65o Tallahasee Hills/Valdosta Limesink 65p Southeastern Floodplains and Low Terraces Southern Coastal Plain 75a Gulf Coast Flatwoods 75d Tampa 75b Southwestern Florida Flatwoods 75c Central Florida Ridges and Uplands 75d Eastern Florida Flatwoods 75e Okefenokee Plains 75b 75f Sea Island Flatwoods 75g Okefenokee Swamps Lake 75i Floodplains and Low Terraces Okeechobee 75j Sea Islands/Coastal Marsh 75k Gulf Barrier Islands and Coastal Marshes 75l Big Bend Coastal Marsh Southern Florida Coastal Plain 76a Everglades 76a 76b Big Cypress 76c 76c Miami Ridge/Atlantic Coastal Strip 76b Miami 76d Southern Coast and Islands
Level III ecoregion Level IV ecoregion State boundary County boundary SCALE 1:940 000 76d 020 40 MILE
020 40 KILOMETER Albers equal area projection Key West
Figure 1. Location of the study area and ecoregions in Florida. 4 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Data Compilation Basin Characteristics
The first step in the regionalization of flood-frequency Peak-flow information can be estimated for ungaged estimates for streams is the compilation of all peak-flow data locations through multiple-regression analysis that relates from streamgages with at least 10 years of annual peak-flow peak-flow characteristics (such as the 1-percent chance record. The annual peak-flow record is reviewed for quality exceedance flow) to selected physical and climatic basin assurance and quality control (QA/QC) and for homogeneity, characteristics for gaged drainage basins. Basin characteristics which implies relatively constant watershed and climatic con- for this study were generated using geographical information ditions during the period of record. Once peak-flow records system (GIS) techniques. Basin boundaries were determined are compiled and reviewed, basin characteristics must be from the National Elevation Dataset (NED) Digital Elevation determined for each streamgage. Models (DEMs) at 10-meter horizontal resolution (U.S. Geo- logical Survey, 1999a). To improve basin boundary delinea- tions, processes were completed to make the DEM conform to Annual Peak Flows stream locations defined in the National Hydrography Dataset (NHD) (U.S. Geological Survey, 1999b) (modified from Got- Annual peak flow is the highest instantaneous flow vald and others, 2009). recorded at a site for an independent flood event during the Basin characteristics were used as potential explana- water year. Occasionally, the annual peak flow is not the maxi- tory variables in the regression analyses based on theoretical mum for the year. In such cases, the maximum flow occurs at hydrologic relation to flood flows and the ability to obtain a midnight at the beginning or end of the water year, on a reces- measurement of the basin characteristics by using digital data- sion from or rise toward a higher peak in an adjoining water sets and GIS technology (modified from Gotvald and others, year. 2009). The following nine basin characteristics were tested for Streamgages with annual peak-flow record are either statistical significance in the regression analysis: continuous-record or crest-stage stations. At continuous- 1. Drainage area (DRNAREA), in square miles: record stations, measured parameters, such as the surface- The area that contributes to surface runoff. water elevation (or stage) of a stream are recorded at fixed time intervals, typically at 15-, 30-, or 60-minute intervals. At 2. Elevation (ELEV), in feet: crest-stage stations, only the highest stage that occurs between The mean basin elevation, in feet above National site visits is recorded. Regardless of the type of gage, mea- Geodetic Vertical Datum of 1929 (NGVD 29). surements of flow are made by field personnel throughout the range of recorded stages, and a relation between stage and 3. Forest (FOREST), in percent: flow (known as a rating) is developed for the streamgage. This The area of forest, expressed as percent, of the rating is used to determine flows for all recorded stages at a contributing drainage area. streamgage. 4. Lake area (LKAREA), in percent: Streamgages in Florida and in adjacent parts of Alabama The surface area of lakes and ponds expressed as a and Georgia that monitor Florida streams were evaluated for percentage of the contributing drainage area. possible inclusion in this investigation. Streamgages were only considered for the analysis if 10 or more years of peak- 5. Swamps (WETLAND), in percent: flow data were available in the record, and if peak flows were The surface area of swamps expressed as a percentage not substantially affected by trends, dam regulation, flood- of the contributing drainage area. retarding reservoirs, tides, urbanization, or channelization. These stations were then reviewed for QA/QC using the tests 6. Storage (STORAGE), in percent: as outlined in Ryberg (2008). The QA/QC analysis determined The surface area of lakes, ponds, and swamps expressed that 305 stations were appropriate for the study, consisting of as a percentage of the contributing drainage area. 275 in Florida, 21 in Georgia, and 9 in Alabama.
Trout Creek near Sulphur Springs, Florida, on the downstream side of the bridge during the flood of September 7, 2004. Stage was 43.01 ft and the flow rate was 1,610 ft3/s. Photograph by USGS. Estimation of Flood Magnitude and Frequency at Gaged Stations 5
7. Channel slope (SL), in feet per mile: Estimation of Flood Magnitude and The average slope of the main channel between points 10 and 85 percent of the distance upstream from the gaging Frequency at Gaged Stations site to the basin divide. A flood-frequency relation is the relation of annual 8. Mean annual precipitation (PRECIP), in inches. peak flow to probability of exceedance or recurrence inter- 9. Average precipitation event size, in inches per day, over val (Hedgecock and Feaster, 2007). Previous USGS reports an 18-year mean. published flood-frequency flows in terms of the T-year event based on the recurrence interval for that flood quantile (for Table 1 describes the basin characteristics considered for example, the “50-year flood”). While the T-year recurrence use in regional regression analysis, including the parameter interval flood is statistically expected to occur, on average, name, units of measure, method, and source data.
Table 1. Basin characteristics considered for use in the regional regression analysis (modified from Gotvald and others, 2009).
[DEM, Digital Elevation Models; NHD, National Hydrography Dataset]
Name Units Method Source data Drainage area Square miles ArcGIS ArcHydro derived using National Elevation Dataset, 10- and 30-meter watershed boundary, DEM, NHDPlus resolution (http://ned.usgs.gov/#), NHDPlus hydrography, and gaging stations hydrography, (http://www.horizon-systems. com/nhdplus/), Watershed, http://www.ncgc. nrcs.usda.gov/products/datasets/watershed/ index.html, NHDPlus hydrography and gaging stations, (http://www.horizon-systems.com/ nhdplus/)
Elevation Feet Area-weighted average National Elevation Dataset, 10- and 30-meter resolution (http://ned.usgs.gov/#)
Forest Percent (Forested area/drainage area)*100 National Land-Cover Dataset 2001 30-meter resolution (http://www.mrlc.gov/index.php).
Lake Percent (Lake area/drainage area)*100 National Land-Cover Dataset 2001 30-meter resolution (http://www.mrlc.gov/index.php).
Swamps Percent (Swamp area/drainage area)*100 National Land-Cover Dataset 2001 30-meter resolution (http://www.mrlc.gov/index.php).
Storage Percent ((Lake area + Swamp area)/drainage National Land-Cover Dataset 2001 30-meter area)*100 resolution (http://www.mrlc.gov/index.php).
Channel slope Feet per mile ArcGIS ArcHydro derived using the ArcGIS ArcHydro calculated using DEM and difference in the DEM elevation at Archydro derived channel length, defined in points along the main channel within the drainage area source data. the drainage area at 10 percent and 85 percent then divided by the length between those points Mean annual precipitation Inches Area-weighted average DATMET, Daily Surface Weather and Climata- logical Summaries (http://www.daymet.org/ climateSummary.jsp)
Average precipitation event Inches Area-weighted average DATMET, Daily Surface Weather and Climata- size, in inches per day, logical Summaries (http://www.daymet.org/ over an 18-year mean climateSummary.jsp) 6 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 once during the T-year period, it may occur multiple times The T-year recurrence intervals with corresponding during the period, or not at all (modified from Gotvald and annual exceedance probabilities and P-percent chance exceed- others, 2009). ance are described in table 2. Because of the potential for misinterpretation, terminology associated with flood-frequency estimates has shifted from the T-year recurrence interval flood to the Log-Pearson Type III Flood-Frequency Analysis P-percent chance exceedance flood. The use of percent chance The flood-frequency relation for a stream having at exceedance flood is recommended because it conveys the least 10 years of record can be defined by fitting a theoretical probability of a flood of a given magnitude being equaled frequency distribution curve to the logarithms of annual peak or exceeded in a given year (Gotvald and others, 2009). For flows. Bulletin 17B (U.S. Water Resources Council, 1982) example, a 1-percent chance exceedance flood (formerly recommends fitting a Pearson Type III distribution to the known as the “100-year flood”) corresponds to the flow logarithms of annual peak flows as the consistent method for magnitude that has a probability of 0.01 of being equaled determining flood magnitudes and frequencies. This tech- or exceeded in a given year. That is, a flow with an annual nique, most commonly referred to as the log-Pearson Type III exceedance probability of 0.01 has a 1 percent chance of being flood-frequency analysis, is generally accepted as the standard equaled or exceeded in a given year. The T-year recurrence technique by most Federal and State agencies (Hedgecock and interval and exceedance probability are the mathematical Feaster, 2007, eq. 1). inverses of one another; therefore, a flood with an exceed- The log-Pearson Type III distribution is defined by the ance probability of 0.01 (1-percent chance exceedance) has a equation: recurrence interval of 1/0.01 or 100 years. Thus, the P-percent chance exceedance is computed as the inverse of the T-year logQM=+KS , (2) recurrence interval multiplied by 100. A 100-year T-year pxpx recurrence interval is equivalent to a 1-percent chance exceed- where ance (1/100-year recurrence interval x 100 = 1-percent chance Q is the P-percent chance exceedance flow, exceedance). A 25-year recurrence interval is equivalent to a p in cubic feet per second; 4-percent chance exceedance (1/25-year recurrence interval M is the mean of the logarithms of the x 100 = 4-percent chance exceedance), and so forth (modi- x water-year peak flows; fied from Feaster and others, 2009). Therefore, the P-percent K is a Pearson Type III factor for a skew chance exceedance is computed as follows: p coefficient G( ) computed from the logarithms of the water-year peak flows
1 and a selected percent chance exceedance P = ×100 , (1) T P; and S is the standard deviation of the logarithms of where x the water-year peak flows. P is the percent chance exceedance T is the T-year recurrence interval The computer program PeakFQWin version 5.2 developed by the USGS was used to compute flood-frequency estimates for the streamgages considered for this study and Table 2. T-year recurrence intervals with corresponding annual the results are included in appendix 1. PeakFQWin automates exceedance probabilities and P-percent chance exceedance for many of the analysis procedures recommended in Bulletin flood-frequency discharge estimates (modified from Gotvald and 17B (U.S. Water Resources Council, 1982), including identify- others, 2009). ing and adjusting for outliers and historical periods, weighting station skews and generalized skews, and fitting a log-Pearson T-year Annual Type III distribution curve to the annual peak-flow data (Flynn P-percent chance recurrence exceedance exceedance and others, 2006; Feaster and others, 2009). interval probability 2 0.50 50 Skew Coefficient 5 0.20 20 10 0.10 10 The skew coefficient is a measure of asymmetry of the 25 0.04 4 probability distribution of a set of annual peak flows. The 50 0.02 2 skew coefficient is strongly influenced by the presence of outliers and is sensitive to extreme events (Feaster and others, 100 0.01 1 2009). For example, an inaccurate estimate of the asymmetry 200 0.005 0.5 of the flood-frequency distribution for an individual station 500 0.002 0.2 can result if a single high event has occurred in a relatively Estimation of Flood Magnitude and Frequency at Gaged Stations 7 short period of record. Thus, the skew coefficient is considered for each model, and the significance level of the independent a less reliable estimator than the mean and standard deviation variables. Based on the investigation of all possible combi- of a population statistic for an individual site, because of its nations of explanatory variables, contributing drainage area significant variability between samples. Several procedures (DRNAREA, eq. 2) was determined to be the most influential have been introduced to improve the reliability of the sample variable followed by the percent of total surface area covered skew coefficient in estimating the population skew. Bulle- by storage (STORAGE, eq. 2), which includes lakes, ponds, tin 17B (U.S. Water Resources Council, 1982) recommends and swamps. Hammett and DelCharco (2005), Bridges (1982), weighting the skew coefficient computed for an individual and Seijo and others (1979) determined that contributing station with a generalized skew coefficient that represents drainage area was the most influential variable in their respec- the average skew for nearby stations. The weighting proce- tive studies; however, each of these investigators concluded dure recommended in Bulletin 17B (U.S. Water Resources that channel slope and lake area were significant factors at the Council, 1982) is different than those in Bulletin 17 (U.S. 0.05 significance level. The regression analysis for this study Water Resources Council, 1976) or Bulletin 17A (U.S. Water included storage, rather than lakes (which does not include the Resources Council, 1977) and tends to reduce the influence of surface area covered by swamps). Additionally, the channel the generalized skew and increase the influence of the station slope variable improved the regression analysis by less than skew (Hammett and DelCharco, 2005). 1 percent, and thus, was not a final variable included in this Program PeakFQ software allows the user to weight the study considering the relatively flat topography of Florida. station skew coefficient with the generalized skew coefficient Log transformations were used for the variables in the to compute the log-Pearson Type III flood-frequency curve regressions, which is an identical technique employed in pre- for a station, as recommended in Bulletin 17B (U.S. Water vious studies. Throughout the State, there were several gages Resources Council, 1982). The generalized skew coefficient where the percent of storage was zero; therefore, it was not used for this study was determined from Bulletin 17B (U.S. possible to transform that characteristic without the addition Water Resources Council, 1982, pl. 1). The weighted skew of a constant for all sites, similar to what was done in previ- combines the station and generalized skews by weighting them ous studies. Adding a small constant is a common practice in inverse proportion to their mean-square errors. Because the when applying log transformations to datasets with some zero mean-square error of the station skew increases as the length values, according to Haan (1977). Hammett and DelCharco of record decreases, weighted skew coefficients for stations (2005) and Bridges (1982) each added constants of 3.0 or 0.6 with short periods of record can be substantially adjusted by for the lake variable depending on which geographic region generalized skews. For stations with longer periods of record, the site was located. For this study, a constant of 1.0 was the station skew has the greater importance in the computa- added to all storage values in the four hydrologic flood regions tion of a weighted skew coefficient (Hammett and DelCharco, (pl. 1). 2005). The log-Pearson Type III flood-frequency curves Multiple-regression techniques were used to delineate the presented in appendix 1 represent computations based on four hydrologic flood regions defined in Florida (pl. 1). These weighted skew coefficients. regions were defined based on the plotted residuals from the multiple-regression analysis. In addition, data from previous flood-frequency studies, and geologic, physiographic, and Regional Flood-Frequency Regression Analysis drainage-area maps were also consulted to help better define these regions. A regional regression analysis was used to mathematically relate basin characteristics to estimates of flood magnitude and frequency at streamgaging stations. Generalized Least-Squares Regression Analysis Explanatory variables for the regional regression analysis were related to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and Generalized least-squares regression methods, as 0.2-percent chance exceedance flows that had been calculated described by Stedinger and Tasker (1985), were used to deter- using Bulletin 17B (U.S. Water Resources Council, 1982) mine final regional P-percent chance exceedance flow regres- criteria. Equations computed from the regression analyses sion equations with the computer program GLSNET devel- can then be used to calculate estimates of flood flows at sites oped by the USGS. An investigation by Tasker and Stedinger where basin characteristics are known, but flow data are (1989) showed that model error from an ordinary least-squares unavailable or insufficient (less than 10 years of available data regression can be reduced by using a generalized least-squares at the gage). (GLS) regression, which takes into account the time-sampling All possible combinations of explanatory variables error of flood-flow characteristics and the correlation of flood- were investigated to determine which basin characteristics flow characteristics between nearby stations. In GLS analysis, were most statistically significant in relation to peak flows. the total prediction error is partitioned into model error and Preliminary regression models were evaluated by examining sampling error, thus making it possible to identify errors due the root mean-square error, coefficient of determination (R2) to inadequacies of model formulation compared with deficien- cies in the database (Hammett and DelCharco, 2005). 8 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Accuracy and Limitations of as the model error. The SEE is computed using the following Flood-Frequency Estimates equation (Gotvald and others, 2009):
05. Empirical results from regression equations are not 2.3026(γ 2 ) SE =−100 10 1 , (5) exact. Regression equations are statistical models that are E interpreted and applied within the limits of the data and with where the understanding that the results are best-fit estimates with an associated scatter or variance. The development and use SEE is the mean standard error of estimate, of a regression equation raises questions about how well the in percent; and predicted values are representative of true values. Errors in the γ2 is the model error variance. model (that is, differences between the predicted and observed values) can be examined to determine parameters that describe The standard error of prediction, SEP, is the square root the accuracy of a regression equation, which depends on both of the mean square error of prediction and is a measure of the model error and the sampling error. Model error mea- how well the regression equation estimates flood flows when sures the ability of a set of explanatory variables to estimate applied to ungaged basins. The SEP is calculated using the the values of peak-flow characteristics calculated from the following equation (Gotvald and others, 2009): station records that were used to develop the equation. The model error depends on the number and predictive power of 05. the explanatory variables in a regression equation. Sampling SE =−100 102.3026(AVP) 1 , (6) error measures the ability of a finite number of stations with P a finite number of recorded annual peak flows to describe the where true characteristics of the entire peak-flow record for a station. SE is the mean standard error of prediction, The sampling error depends on the number and record length p in percent; and of stations used in the analysis, and decreases as the number AVP is the average variance of prediction. of stations and record lengths increase (modified from Gotvald and others, 2009). A measure of uncertainty in a regression equation The regression equations and errors presented in table 3 (eq. 7-38) are only applicable when the equations are used for estimate for a site, i, is the variance of prediction, Vp,i. The Vp,i is the sum of the model error variance and sampling error sites where the values of basin characteristics fall within the variance and is computed using the following equation range of values used to develop the equations. Extrapolating (Gotvald and others, 2009): the regression equations for use in watersheds that have char- acteristics outside the valid range would produce flood-flow estimates with unpredictable errors. A constant of 1.0 is added 2 VMpi, =+γ SEsi, , (3) to storage when using the regression equations defined in where table 3 for the reasons previously discussed. Table 4 describes γ2 is the model error variance; and the valid ranges of basin characteristics for each hydrologic region, as defined in this study. Figure 2 shows the distribution MSEs,i is the sampling mean square error for the site, i, of drainage area and storage. For example, Region 3 has an apparent outlier with 91 percent storage, but the limiting value Assuming that the explanatory variables for the gaged for the region is 48 percent storage. A regression of drainage stations in a regression analysis are representative of all sta- area alone versus the 1-percent chance exceedance shows the tions in the region, the average accuracy of prediction for point plots within the general trend of the data; therefore, the a regression equation can be determined by computing the site was left in the regression. However, there is not enough average variance of prediction, AVP, for n number of stations data in the range to verify it truly works, so that is the reason (Gotvald and others, 2009): for limiting the valid range for storage to 48 percent.
n 2 1 Regression equations 7-38 are shown on table 3 (7-38) AVP =+γ ∑ MSEsi, , (4) n i=1 Previous USGS flood-frequency reports expressed the where variables are as previously defined. accuracy of the regional regression equations in terms of equivalent length of record (in years), which is an estimate of Traditionally, accuracy of a flood-frequency relation has the number of years of station data needed at an ungaged site been expressed two ways—the mean standard error of esti- to produce peak-flow estimates with accuracy equal to that mate, SEE, or as the mean standard error of prediction, SEP. of the associated regression equation. The equivalent length- The SEE is a measure of how well the regression equation of-record concept can sometimes misconstrue the relation fits the data used to derive the relation and is often referred to between flood-frequency estimates and associated variances. Estimation of Flood Magnitude and Frequency at Gaged Stations 9
Table 3. Regression equations for geographic regions in Florida.
[n, number of stations used in analysis. Table includes equations 7-38 referenced in the text]
Standard Standard Equivalent Average Average Exceedance Average Regression Equation error of error length of sampling variance of probability model error equations number prediction of estimate record error prediction (percent) (log units) (percent) (percent) (years) (log units) (log units) Region 1 (n=77) 50 Q=127A0.656(ST+1)-0.098 7 43 42 2.68 0.0018 0.0307 0.0325 20 Q=248A0.662(ST+1)-0.189 8 40 39 4.84 0.0019 0.0262 0.0281 10 Q=357A0.666(ST+1)-0.239 9 42 40 6.19 0.0022 0.0287 0.0309 4 Q=528A0.671(ST+1)-0.293 10 47 45 7.26 0.0028 0.0353 0.0381 2 Q=684A0.675(ST+1)-0.328 11 52 50 7.69 0.0034 0.0418 0.0452 1 Q=864A0.679(ST+1)-0.362 12 57 55 7.92 0.0040 0.0493 0.0533 0.5 Q=1072A0.683(ST+1)-0.392 13 62 60 8.02 0.0046 0.0576 0.0622 0.2 Q=1395A0.688(ST+1)-0.430 14 70 67 8.03 0.0055 0.0700 0.0755 Region 2 (n=83) 50 Q=101A0.617(ST+1)-0.211 15 58 57 1.79 0.0026 0.0529 0.0555 20 Q-184A0.620(ST+1)-0.212 16 53 51 2.70 0.0024 0.0443 0.0467 10 Q=253A0.621(ST+1)-0.215 17 52 50 3.69 0.0025 0.0427 0.0452 4 Q=353A0.621(ST+1)-0.221 18 53 51 4.94 0.0027 0.0435 0.0462 2 Q=435A0.621(ST+1)-0.226 19 54 52 5.73 0.0030 0.0455 0.0485 1 Q=525A0.621(ST+1)-0.231 20 56 54 6.34 0.0033 0.0485 0.0518 0.5 Q=622A0.621(ST+1)-0.236 21 59 56 6.80 0.0036 0.0523 0.0559 0.2 Q=764A0.620(ST+1)-0.244 22 63 60 7.19 0.0041 0.0584 0.0625 Region 3 (n=76) 50 Q=72.7A0.741(ST+1)-0.589 23 87 85 0.99 0.0048 0.1023 0.1071 20 Q=164A0.704(ST+1)-0.587 24 62 60 2.07 0.0031 0.0588 0.0619 10 Q=250A0.686(ST+1)-0.592 25 56 54 3.23 0.0028 0.0486 0.0514 4 Q=390A0.668(ST+1)-0.601 26 53 52 4.77 0.0028 0.0444 0.0472 2 Q=517A0.656(ST+1)-0.608 27 53 52 5.74 0.0030 0.0444 0.0474 1 Q=664A0.646(ST+1)-0.616 28 54 52 6.52 0.0032 0.0459 0.0491 0.5 Q=833A0.638(ST+1)-0.625 29 56 54 7.11 0.0034 0.0482 0.0516 0.2 Q=1094A0.629(ST+1)-0.638 30 59 56 7.68 0.0038 0.0522 0.0560 Region 4 (n=69) 50 Q=171A0.628(ST+1)-0.401 31 36 35 4.15 0.0017 0.0218 0.0235 20 Q=321A0.618(ST+1)-0.395 32 39 38 4.86 0.0020 0.0250 0.0270 10 Q=447A0.614(ST+1)-0.396 33 43 41 5.54 0.0024 0.0293 0.0317 4 Q=636A0.610(ST+1)-0.401 34 48 46 6.19 0.0030 0.0365 0.0395 2 Q=797A0.609(ST+1)-0.406 35 53 50 6.48 0.0035 0.0427 0.0462 1 Q=975A0.608(ST+1)-0.411 36 57 55 6.64 0.0040 0.0496 0.0536 0.5 Q=1171A0.608(ST+1)-0.416 37 62 59 6.71 0.0046 0.0571 0.0617 0.2 Q=1461A0.609(ST+1)-0.424 38 69 66 6.70 0.0054 0.0681 0.0735 10 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Table 4. Valid ranges of basin characteristics for the Using variances provides a more accurate characterization of regional regression equations. the underlying uncertainty of the various flow estimates.
[mi2, square miles] Weighting of Log-Pearson Type III and Basin Minimum Maximum Regression Analyses characteristic in region in region Region 1 Flood estimates at streamgages for a selected exceedance Drainage area (mi2) 0.14 4385 probability can be determined by weighting the regional and Storage (percent) 0.00 44.29 station flood estimates for the specified exceedance probability Region 2 using the variance of prediction for each of the two estimates. Drainage area (mi2) 0.06 2647 The variance of prediction can be considered as a measure of the uncertainty in either the streamgage flow estimate or the Storage (percent) 0.00 74.33 regional regression results. If the two estimates are assumed Region 3 to be independent and are weighted in inverse proportion to Drainage area (mi2) 0.41 3244 the associated variances, the variance of the weighted estimate Storage (percent) 0.18 48.04 will be less than the variance of either of the independent Region 4 estimates. Drainage area (mi2) 0.20 2833 The variance of prediction corresponding to the Storage (percent) 0.00 34.12 streamgage-flow estimate from the log-Pearson Type III analysis is computed using the asymptotic formula given in
50 100 45 Region 1 Variable Distribution 90 Region 2 Variable Distribution 40 80 35 70 30 60 25 50 20 40 15 30 10 20
ST (STORAGE, IN PERCENT) ST (STORAGE, IN PERCENT) 5 10 0 0 -1 0 1 234 -2 -1 0 1 234 LOG DRAINAGE AREA LOG DRAINAGE AREA
100 40 Region 3 Variable Distribution Region 4 Variable Distribution 90 35 80 30 70 60 25 50 20 40 15 30 20 10
ST (STORAGE, IN PERCENT) ST (STORAGE, IN PERCENT) 10 5 0 0 -1 0 1 234 -1 0 1 234 LOG DRAINAGE AREA LOG DRAINAGE AREA
Figure 2. Distribution of drainage area and storage for the four hydrologic regions in Florida. Estimation of Flood Magnitude and Frequency at Gaged Stations 11
Cohn and others (2001) with the addition of the mean-squared Qp(g)s is the estimate of peak flow at the gaged error of generalized skew (Griffis and others, 2004). This vari- station from the log-Pearson Type III ance varies as a function of the length of record and the fitted analysis for the selected P-percent chance log-Pearson Type III distribution parameters (mean, standard exceedance, in cubic feet per second; deviation, and weighted skew). The variance of prediction for Vp,P(g)s is the variance of prediction at the gaged the streamgage flow estimate generally decreases with length station from the log-Pearson Type III of record and the quality of the log-Pearson Type III distribu- analysis for the selected P-percent chance tion fit. The variance of prediction values for the streamgage- exceedance, in log units; and flow estimates for the 275 streamgages in Florida are shown Qp(g)r is the peak-flow estimate for the P-percent in appendix 2. The variance of prediction from the regression chance exceedance at the gaged station equations is a function of the regression equations and the derived from the applicable regression values of the independent variables used to develop the flow equation, in cubic feet per second. estimate from the regression equations. This variance gener- When the variance of prediction corresponding to one ally increases as the values of the independent move further of the estimates is high, the uncertainty also is high, so the from the mean values of the independent variables. Once the weight for that estimate is relatively small. Conversely, when variances have been computed, the two independent-flow esti- the variance of prediction is low, the uncertainty also is low, so mates can be weighted using the following equation (Feaster the weight is correspondingly large. The variance of prediction and others, 2009; Gotvald and others, 2009): associated with the weighted estimate, Vp, P(g)w, is computed using the following equation (Feaster and others, 2009 Gotvald and others, 2009): VQpP,(gr)(loglPg),sp+VQPg()sPog ()gr , (39) log Q P(g)w = VVpP,(gs) + p, Pg()r VVpP,(gs),pP()gr VpP,(gw) = , (40) VVpP,(gs),+ pP()gr where
where variables are as previously defined. QP(g)w is the weighted estimate of peak flow for any P-percent chance exceedance for a gaged Weighted flood-flow estimates for the 305 streamgages station, in cubic feet per second; used in this study are presented in appendix 1, along with the log-Pearson Type III distribution and regression results. Vp,P(g)r is the variance of prediction at the gaged station derived from the regression equation for the selected P-percent chance exceedance, in log units;
Aerial view near the Alapaha River near Jennings, Florida, during the flood of April 2009. Photograph by the Fish and Wildlife Commission. 12 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Estimation of Flood Magnitude and the drainage areas of the gaged site and the ungaged site, in square miles;
Frequency at Ungaged Stations A(g) is the drainage area for the gaged site, in square miles; and
Peak-flow estimates have been calculated for QP(u)r is the peak-flow estimate derived from the 275 streamgages in Florida, 21 in Georgia, and 9 in Alabama applicable regional equations for the for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent chance selected P-percent chance exceedance at exceedance flows. However, flood-flow estimates are the ungaged site, in cubic feet per second. frequently needed for locations on a stream where little (less than 10 years of data) to no-flow data are available. Flood- Use of this equation gives full weight to the regression flow estimates for these streams can be derived by directly equation estimates when the drainage area for the ungaged site applying the regional regression equations (table 3) for the is equal to 0.5 or 1.5 times the drainage area for the gaged site, respective hydrologic regions (pl. 1). and increasing weight to the gaged site estimates as the ratio Methods for improved flood-frequency estimates for an of the drainage area approaches 1. The weighting procedure ungaged site near a gaged site on the same stream with more must not be applied when the drainage-area ratio for the than 10 years of peak-flow data were presented by Sauer ungaged site and gaged site is less than 0.5 or greater than 1.5
(1974). To obtain a weighted peak-flow estimate Q( P(u)w) for (Feaster and others, 2009; Gotvald and others, 2009). P-percent chance exceedance at the ungaged site, the weighted An example of the application of the procedure described peak-flow estimate for a downstream or upstream gaged in this section is the following computation of the weighted site (QP(g)w) must first be determined using equation 39. The 1-percent chance exceedance flow for a hypothetical ungaged weighted peak-flow estimate for the ungaged site Q( P(u)w) is site on the New River located above the USGS station near then computed using the following equation: Sumatra, Florida (station number 02330400, site 255, pl. 1) (Gotvald and others, 2009): 3 2∆∆A 2 A QPg()w 1. Calculate the value of Q (Q =7,010 ft /s); , (41) 1%(g)w 1%(g)w QPu()w = +−1 QPu()r A()gg A() QPg()r 2. Obtain the drainage areas for both the gaged and ungaged 2 2 where sites (Ag=151 mi , and Au=115 mi );
Q is the weighted estimate of peak flow for the 3. Obtain the storage factor for both the gaged and ungaged P(u)w sites (ST =43.03, and ST =30.1); selected P-percent chance exceedance at g u the ungaged site, in cubic feet per second; 4. Compute Q1%(u)r for the ungaged site using equation 12 ΔA is the absolute value of the difference between ((864*(1150.679))(31.1-0.362))=6,240 ft3/s;
Table 5. Comparison of Bulletin 17B (U.S. Water Resources Council, 1982) flood-discharge estimates from this investigation with Bulletin 17 (U.S. Water Resources Council, 1976) or Bulletin 17A (U.S. Water Resources Council, 1977) estimates from previous investigations.
[N, number of years of record used in the analysis]
Flood discharge (in cubic feet per second) Investigator P-percent chance exceedance N 50 20 10 4 2 1 0.5 0.2 02300000 Manatee River near Bradenton, Florida; map number 136 This investigation (2011) 27 2,420 4,530 6,240 8,770 10,900 13,200 15,800 19,500 Bridges (1982) 27 2,410 4,520 6,260 8,840 11,000 13,400 16,100 20,100 Seijo and others (1979) 27 2,360 4,490 6,340 9,230 11,800 14,800 18,200 23,500 02322500 Santa Fe River near Fort White, Florida; map number 212 This investigation (2011) 75 3,860 6,610 8,720 11,700 14,100 16,700 19,400 23,400 Bridges (1982) 47 4,120 6,870 8,940 11,800 14,100 16,500 19,100 22,800 Seijo and others (1979) 45 4,170 7,060 9,340 12,600 15,400 18,300 21,600 26,400 02297100 Joshua Creek at Nocatee, Florida; map number 120 This investigation (2011) 56 1,760 3,180 4,380 6,260 7,930 9,860 12,100 15,500 Bridges (1982) 28 1,920 3,570 4,930 6,950 8,660 10,500 12,600 15,700 Seijo and others (1979) 26 1,960 3,710 5,240 7,630 9,770 12,200 15,100 19,500 Estimation of Flood Magnitude and Frequency at Ungaged Stations 13
5. Compute Q1%(g)r for the gaged site using equation 12 weighted on the percentage of drainage area in each flood 3 (Q1%(g)r =6,640 ft /s); region. The same procedure applies to sites on streams that cross state boundaries where different methods are used for 2 6. Compute ΔA, where ΔA =151-115=36 mi ; estimating flood magnitudes. 7. Compute the weighted estimate for the ungaged site, Q , using equation 41 (Q =[((2*36)/151)+ p(u)w 1%(u)w Comparison with Previous Analyses ((1-((2*36)/151))*(7,010/6,640))]*6,240=6,420 ft3/s . Estimates of flood flows for three stations used in this For an ungaged site that is located between two gaged investigation are compared to estimates presented by Bridges stations on the same stream, two flow estimates can be made (1982) and Seijo and others (1979) to illustrate the effects of using the methods and criteria outlined in this section. In addi- changes in methodology, regression equations, and record tion to evaluating the differences in hydrologic region make- length (tables 5, 6, and 7). Manatee River near Bradenton was up of the two gaged stations in comparison to the ungaged site, chosen for comparative purposes and, because the site was hydrologic judgment may be necessary to determine which of discontinued in 1966, the same period of record was used the two estimates is most appropriate. Other factors may need in all three investigations. Santa Fe River near Fort White consideration when evaluating the two estimates, including the and Joshua Creek at Nocatee each have substantially longer differences in the length of record for the two gaged stations lengths of record now than when they were analyzed in the and the hydrologic conditions that existed during the data col- Bridges (1982) and Seijo and others (1979) reports, and these lection period for each gaged station. For example, does the sites were chosen as representing sites with additional data for time series represent a climatic period that was predominately analysis in the present study. wet or dry? (Modified from Gotvald and others, 2009.) Table 5 shows the effects of both additional records and changes in methods during the last 30 years of estimating flood flows using log-Pearson Type III analyses. Manatee Sites on Streams that Cross Flood Region River near Bradenton, for example, has 27 years of annual or State Boundaries peak-flow data and all three investigations used this same period of record. This investigation used the U.S. Water For streams that cross flood region boundaries, flood Resources Council (1982) Bulletin 17B guidelines to com- magnitudes can be estimated by weighting the flood estimate pute flood flow. The investigation by Bridges (1982) used the by the percentage of basin drainage area in each flood region. guidelines presented in Bulletin 17A (U.S. Water Resources First, the flood estimate is computed as if the total drainage Council, 1977). The work by Seijo and others (1979) used area lies in each flood region. Next, the flood estimates are the guidelines presented in Bulletin 17 (U.S. Water Resources
Table 6. Comparison of regression equation flood-discharge estimates from this investigation with regression equation flood-discharge estimates from previous investigations.
[N, number of years of record used in the analysis]
Flood discharge (in cubic feet per second) Investigator P-percent chance exceedance N 50 20 10 4 2 1 0.5 0.2 02300000 Manatee River near Bradenton, Florida; map number 136 This investigation (2011) 27 1,570 2,850 3,890 5,380 6,660 8,050 9,590 11,900 Bridges (1982) 27 1,640 2,990 4,060 5,610 6,890 8,280 9,740 11,900 Seijo and others (1979) 27 1,810 3,360 4,690 6,760 8,600 10,700 13,100 16,900 02322500 Santa Fe River near Fort White, Florida; map number 212 This investigation (2011) 75 4,190 7,780 10,700 14,700 17,900 21,300 24,900 29,700 Bridges (1982) 47 2,620 4,890 6,720 9,410 11,700 15,200 16,800 20,900 Seijo and others (1979) 45 4,050 6,900 9,200 12,600 15,400 18,600 22,100 27,400 02297100 Joshua Creek at Nocatee, Florida; map number 120 This investigation (2011) 56 2,040 3,670 5,010 6,940 8,590 10,400 12,400 15,300 Bridges (1982) 28 2,180 3,910 5,290 7,280 8,930 10,700 12,600 15,400 Seijo and others (1979) 26 2,670 4,900 6,800 9,730 12,300 15,300 18,700 23,900 14 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Council, 1976), which used only a generalized skew, rather overestimation of flows at all three example locations, which than a map skew weighted with the station skew (Hammett is probably the reflection of different methods used during and DelCharco, 2005). Comparing this study with the Bridges their study. (1982) study shows less than a 1-percent difference in esti- mated flood flows at the 2-percent chance exceedance level, less than 2-percent difference at the 0.5- and 1-percent chance exceedance levels, and less than 3-percent difference at the Effects of Flood Distribution and 0.2-percent chance exceedance level. The report by Seijo and Magnitude in the Peak-Flow Dataset others (1979) shows a much wider variance in results because the study utilized only a generalized skew over the weighted Table 8 shows a comparison of the weighted flood-flow skew. For example, at the 0.2-percent chance exceedance, the estimates from this investigation with the weighted estimates difference between the Seijo and others (1979) study and this from the Bridges (1982) investigation. The comparison shows study is about 17 percent. At the 50-percent chance exceed- the effects of flood distribution and magnitude throughout ance, the difference is less than 3 percent. the dataset at three selected stations. The weighted estimates Table 6 shows the differences in the regressions estimates from Bridges (1982) investigation and this investigation at derived by the three studies. The differences in regression Choctawhatchee River near Bruce (station number 02366500, estimates are attributed to the evolution in methods, longer map number 278, pl. 1) indicate little change in distribution lengths of record, changes in geographic groupings, and or magnitudes of floods during the period of record at the site. changes in explanatory variables used in the equations. This The estimates are within 2 percent of the previously published study used contributing drainage area and percent covered by data and the new data. Flood magnitudes appear to be evenly storage as explanatory variables. Bridges (1982) and Seijo and distributed with no high outliers during the 76-year period of others (1979) each used contributing drainage area, channel systematic record. The peak-flow data are available online as slope, and percent covered by lakes in their investigations. supplemental data at https://pubs.usgs.gov/sir/2011/5034. Seijo and others (1979) used soil index as an additional vari- The weighted estimates for Little River near Quincy able in their regression equations. (station number 02329500; map number 243, pl. 1) show the Table 7 shows the weighted flood-discharge flow esti- effects of a dataset where large magnitude floods occurred mates derived in this study compared to those from Bridges in the early part of the systematic record. The current study (1982) and Seijo and others (1979). The difference in weighted estimates approximately 7 percent less water now than was estimates at Manatee River near Bradenton can be attributed estimated in the Bridges (1982) investigation for the 1-percent to the differences in methodology, lengths of record, and chance exceedance probability. An analysis of the peak-flow several additional high-water events that have occurred since data indicates that of the top five floods at the site, only two the Bridges (1982) and Seijo and others (1979) investigations. have occurred since 1978 (the end of the period of analysis The Seijo and others (1979) investigation has a noticeable for the Bridges (1982) investigation)—one in 1984 (rank 5;
Table 7. Comparison of weighted flood-discharge estimates from this investigation with weighted estimates from previous investigations.
[N, number of years of record used in the analysis]
Flood discharge (in cubic feet per second) Investigator P-percent chance exceedance N 50 20 10 4 2 1 0.5 0.2 02300000 Manatee River near Bradenton, Florida; map number 136 This investigation (2011) 27 2,260 4,200 5,740 7,900 9,680 11,500 13,600 16,600 Bridges (1982) 27 2,290 4,240 5,790 8,050 9,990 12,000 14,400 17,600 Seijo and others (1979) 27 2,300 4,230 5,880 8,390 10,700 13,300 16,200 20,900 02322500 Santa Fe River near Fort White, Florida; map number 212 This investigation (2011) 75 3,860 6,640 8,800 11,900 14,400 17,100 20,000 24,200 Bridges (1982) 47 4,050 6,730 8,790 11,600 13,900 16,400 18,800 22,500 Seijo and others (1979) 45 4,160 7,040 9,320 12,600 15,400 18,400 21,700 26,700 02297100 Joshua Creek at Nocatee, Florida; map number 120 This investigation (2011) 56 1,780 3,210 4,440 6,350 8,030 9,960 12,100 15,500 Bridges (1982) 28 1,950 3,620 4,990 7,010 8,710 10,500 12,600 15,600 Seijo and others (1979) 26 2,020 3,940 5,600 8,240 10,600 13,200 16,300 21,000 Flood-Frequency Analysis for Large Streams 15
16,200 ft3/s) and one in 1991 (rank 4; 18,700 ft3/s). However, Flood-Frequency Analysis for the top three floods were substantially larger in magnitude and most likely influenced the results published in 1982, because Large Streams of a relatively short period of record used in the analysis at that time. The top ranking flood occurred in 1969 (45,600 Flood-frequency relations for streamgages along the ft3/s); second ranking flood occurred in 1965 (25,400 ft3/s); main stem of the Apalachicola River and Suwannee River at and the third ranking flood occurred in 1960 (23,300 ft3/s). Ellaville and below (figs. 3–4) were not determined using the The peak-flow data are available online as supplemental data regional flood-frequency analysis, because the drainage areas at https://pubs.usgs.gov/sir/2011/5034. of these sites are substantially larger than the maximum drain- The weighted estimates for the Yellow River at Milligan age areas for the streamgages used in the regional analyses. (station number 02368000, map number 283, pl. 1) show the Additionally, the streamgages on the Apalachicola River are effects of a dataset where large magnitude floods occur in subject to regulation at Jim Woodruff Dam at Lake Seminole the latter part of the systematic record. The current investi- (pl. 1). Where the data analysis indicated it was appropri- gation estimates approximately 45 percent more water now ate, however, relations of flood magnitudes to drainage area than was estimated in the Bridges (1982) investigation for the were determined for selected exceedance probabilities. The 1-percent chance exceedance probability. An analysis of the flood-frequency relations for each river are summarized in the peak-flow data indicates four of the top five floods at the site following sections. The estimated flood-frequency flows were have occurred since the Bridges (1982) investigation—all in based on log-Pearson Type III analyses of peak-flow data at the 1990s. Until 1978 (the end of the period of analysis for the gaged sites on the streams, as described by the Bulletin the Bridges (1982) investigation), the largest flood during the 17B (U.S. Water Resources Council, 1982) guidelines, and systematic record was 38,600 ft3/s, recorded in 1975 (rank 4 are listed in appendix 3. Visual and graphical inspection of of the top 5). Since then, however, four more large floods have the data for each analysis indicated that a log-Pearson Type occurred, three of which are substantially larger than that of III distribution was a reasonable fit for the frequency curves 1975. The top three ranking floods in the systematic record published in this report. occurred in 1999 (rank 1; 82,800 ft3/s), 1998 (rank 2; 55,600 Because the gages along the Apalachicola River have ft3/s), and 1990 (rank 3; 51,500 ft3/s). The peak-flow data are been affected by regulation of flows from Jim Woodruff Dam available online as supplemental data at https://pubs.usgs.gov/ since 1957 (when the dam was constructed), trend analyses sir/2011/5034. for the annual peak flows were performed to test if regulated patterns have changed with time. Trend analyses also were performed at the gages along the Suwannee River at Ellaville and below to test whether flow patterns have changed with time within the basin. Trends in regulations and flow were examined using Kendall’s tau trend analysis and cumulative
Table 8. Comparison of weighted flood-discharge estimates from this investigation with weighted estimates from the Bridges (1982) investigation.
[N, number of years of record used in the analysis]
Flood discharge (cubic feet per second) Investigator P-percent chance exceedance N 50 20 10 4 2 1 0.5 0.2 02366500 Choctawhatchee River near Bruce, Florida; map number 278 This investigation (2011) 76 31,300 49,000 63,600 85,800 106,000 128,000 154,000 194,000 Bridges (1982) 48 31,400 50,000 64,800 87,100 106,000 128,000 153,000 190,000 Percent change 0 -2 -2 -1 0 0 1 2 02329500 Little River near Quincy, Florida; map number 243 This investigation (2011) 41 4,250 9,370 14,300 22,600 30,600 40,000 51,200 69,400 Bridges (1982) 28 4,270 9,850 15,100 24,000 32,600 43,000 55,400 75,500 Percent change 0 -5 -5 -6 -6 -7 -8 -8 02368000 Yellow River at Milligan, Florida; map number 283
This investigation (2011) 66 8,520 17,300 25,600 39,200 51,900 66,600 83,700 111,000 Bridges (1982) 40 8,310 14,900 20,500 29,200 37,000 45,900 56,100 71,800 Percent change 3 16 25 34 40 45 49 55 16 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 plots of weekday daily-mean flows (single-mass curves, location of the storm causing a flood will impact flood esti- Helsel and Hirsch, 1995). Analysis plots included: mates. If, for example, a storm was located in the lower part of (1) cumulated ratio of 90- to 50-percentile daily-value stream- a basin, the streamgages in the upper half of the basin would flow by water year, (2) cumulated weekday 50-percentile not record the runoff associated with the storm. Consequently, streamflow by water year, (3) cumulated water-year mean it is conceivable that a flood of record at a lower gage may not weekday streamflow, (4) cumulated water-year mean weekend necessarily be a flood of record at an upper streamgage. As a streamflow, (5) cumulated ratio of 10- to 50-percentile stream- result of these factors, exceedance probability flood estimates flow by climatic year, and (6) cumulated weekday between two streamgages on the same stream may not be 50-percentile streamflow by climatic year. The single-mass completely linear. However, linearly interpolating between curve is a basic analytical tool showing a plot of cumula- two streamgages with relatively similar lengths of record can tive values against time. The slope of the single-mass curve provide a reasonable estimate of flood magnitudes between the represents the constant of proportionality between the two two streamgages (Hedgecock and Feaster, 2007). quantities (Searcy and Hardison, 1960). A break in the slope of the curve would indicate a sudden change in the proportional- ity constant. This analysis is particularly useful for regulated Apalachicola River streams, because it can determine whether or not regulation The relation of flood flow to drainage area for selected has remained consistent throughout the regulation period. exceedance probabilities for the Apalachicola River is shown Flood magnitudes for selected exceedance probabilities in figure 3 (Hedgecock and Feaster, 2007). Flow patterns at can be estimated by using figures 3–4 by reading the flow all streamgages along the Apalachicola River are impacted scale for the known drainage areas. Peak-flow data at selected by regulation predominantly from Jim Woodruff Dam. Trend sites on these large streams are included in appendix 3 of this assessments, using Kendall’s tau and single-mass curves, were report. The curves in figures 3–4 have been drawn as straight made for the entire period of record from 1920 through 2006 lines connecting the plotted data points. These linear represen- for the Apalachicola River at Chattahoochee (station number tations do not infer that flood estimates or drainage area varies 02358000, pl. 1). Neither of the tests indicated a trend in the uniformly along the stream. The exceedance probability flood data for the high-flow regime. Trend assessments also were estimates at multiple streamgages along a stream will vary as a made for the period from 1957 through 2006, which is the result of several factors, including length of record, concurrent period of regulated peaks. Kendall’s tau statistic indicated a period of record, and intervening tributaries. Additionally, the slightly negative trend in the peak-flow data; however, this
400,000 APALACHICOLA RIVER EXPLANATION Chattahoochee-02358000 350,000 Blountstown-02358700 Sumatra-02359170 0.2 300,000
0.5 250,000 1.0
2.0 200,000 4.0
, IN CUBIC FEET PER SECOND 150,000 10
20 100,000
P-PERCENT CHANCE EXCEEDANCE 50
STREAMFLOW 50,000
0 17,000 17,500 18,000 18,500 19,000 19,500 DRAINAGE AREA
Figure 3. Relation of flood streamflow to drainage area for selected streamgaging stations and P-percent chance exceedance for the Apalachicola River in Florida. Flood-Frequency Analysis for Large Streams 17 trend is most likely the result of the drought that persisted Assessments were made for the Apalachicola River through much of the last decade of record. Single-mass curve near Sumatra (station number 02359170, pl. 1) for the period results show a decreasing trend. Additionally, an analysis of of record from 1978 through 2006. An analysis of the daily the daily mean flows shows a difference in the pattern of daily mean flows shows that 2000 through 2006 was a particularly mean flows after about 1980. This could be because the late dry period, similar to the Chattahoochee and Blountstown 1960s and 1970s was a relatively wet period in the south- streamgages. Trend assessments were performed using Ken- east and not just an issue of changing regulation patterns. A dall’s tau statistic, which provided a value of 0.051. A value peak-flow analysis using only the regulated peaks from 1957 of less than 0.05 indicates a trend in the data. Similar to the through 2006 indicates that the log-Pearson Type III distri- Chattahoochee and Blountstown streamgages, the drought bution provides a reasonable fit of the data. The results for years at the end of the record are the most probable reason for selected exceedance probabilities are shown in appendix 3. Kendall’s tau indicating a negative trend at the 0.05 signifi- The results displayed herein assume that similar regulation cance level. A peak-flow analysis using the regulated peaks patterns will continue in the future. from 1978 through 2006 provides a reasonable fit of the data. Trend assessments were made for Apalachicola River The results for selected exceedance probabilities are shown in near Blountstown (station number 02358700, pl. 1). Similar appendix 3. The results displayed herein assume that similar to the results at the Chattahoochee streamgage, Kendall’s tau regulation patterns will continue in the future. statistic and the single-mass curves indicate a slightly negative trend in the data. Again, this is assumed to be predominantly the result of the drought that occurred during most of the last Suwannee River decade. Additionally, similar to the data at Chattahoochee, The relation of flood flow to drainage area for selected daily-mean flow patterns at the Blountstown streamgage exceedance probabilities for the Suwannee River is shown changed after about 1980 and are most likely attributed to the in figure 4. Flood flows for selected exceedance probabili- change in climatic conditions previously discussed. A peak- ties for the Suwannee River near Benton (station number flow analysis using the regulated peaks from 1958 through 02315000, map number 188, pl. 1), at White Springs (station 2006 provides a reasonable fit of the data. The results for number 02315500, map number 190, pl. 1), and at Suwannee selected exceedance probabilities are shown in appendix 3. Springs (station number 02315550, map number 191, pl. 1) The results displayed herein assume that similar regulation are given in appendix 1. These flows are the log-Pearson Type patterns will continue in the future. III analysis, the regional flood equation estimates, and the
160,000 SUWANNEE RIVER
140,000 EXPLANATION Benton-02315000 White Springs-02315500 120,000 Suwannee Springs-02315550 Ellaville-02319500 Luraville-02320000 100,000 Branford-02320500 0.2
CEEDANCE Bell-02323000 0.5 80,000 Wilcox-02323500 1.0
, IN CUBIC FEET PER SECOND 2.0 60,000 4.0
P-PERCENT CHANCE EX 40,000 10 20
STREAMFLOW 20,000 50
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 DRAINAGE AREA
Figure 4. Relation of flood streamflow to drainage area for selected streamgaging stations and P-percent chance exceedance for the Suwannee River in Florida. 18 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 weighted estimates between these two calculations. The flood analysis and single-mass curves for the entire period of record flows shown on figure 4 are those of the log-Pearson Type III from 1928, 1931, 1942, and 1944 through 2006 indicated no analysis and are based on the period of record from 1973 and change in flow patterns. A log-Pearson Type III analysis was 1976 through 2002 at Benton, 1907 through 1908 and 1928 performed for the period of record and the resulting flood through 2006 at White Springs, and 1961 through 1964 and flows for selected exceedance probabilities are provided in 1966 through 1996 at Suwannee Springs. appendix 3. For the Suwannee River at Ellaville (station number Generally, rainfall from a storm equally dispersed 02319500, pl. 1), a trend test using Kendall’s tau trend analy- throughout a basin means that flood magnitudes will increase sis and single-mass curves for the entire period of record from along with increasing drainage area. This is not the case in the 1928 through 2006 indicated no change in flow patterns. A Suwannee River between Luraville (station number 02320000, log-Pearson Type III analysis was performed for the period of pl. 1) and Branford (station number 02320500, pl. 1). A record and the resulting flood flows for selected exceedance decrease in flood magnitude exists that could be due to peak probabilities are provided in appendix 3. attenuation as cross-sectional area increases in a downstream For the Suwannee River at Branford (station num- direction. A large part of the attenuation is through transient ber 02320500, pl. 1), a trend test using Kendall’s tau trend stream losses to springs which effectively become sinks at analysis and single-mass curves for the entire period of record periods of high stream levels. The same phenomenon of peak from 1928 and 1932 through 2006 indicated no change in flow attenuation occurs between Worthington Springs (station num- patterns. A log-Pearson Type III analysis was performed for ber 02321500, map number 204, pl. 1) and High Springs on the period of record and the resulting flood flows for selected the Santa Fe River (station number 02322000, map exceedance probabilities are provided in appendix 3. number 209, pl. 1; Giese and Franklin, 1996). For the Suwannee River near Wilcox (station number 02323500, pl. 1), a trend test using Kendall’s tau trend
Rising floodwaters affect wildlife habitats and often cause species to seek safety in unfamilar environments. Above: View of a reflector sign near a road near the Suwannee Above: An emu observes standing water and USGS surveying River near Ellaville, Florida, gage during the flood of April 2009. equipment after a heavy rain event in south Florida (circa Ants are maneuvering up the sign to avoid drowning in the 1999–2000). Photographs by Richard Verdi, USGS. floodwaters. Photograph by Mark Stephens, USGS. References Cited 19
Summary References Cited
Flood flows for selected exceedance probabilities were Barnes, H.H., Jr., and Golden, H.G., 1966, Magnitude and determined for 275 streamgages on natural streams in Florida frequency of floods in the United States—Part 2-B of using the log-Pearson Type III frequency distribution. The data South Atlantic Slope and Eastern Gulf of Mexico basins, for these sites in Florida and 30 additional sites in parts of the Ogeechee River to Pearl River: U.S. Geological Survey adjacent States of Georgia and Alabama were used to develop Water-Supply Paper 1674, 409 p. regional flood-frequency relations that can be used to estimate flood flows for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and Bridges, W.C., 1982, Technique for estimating magnitude 0.2-percent chance exceedance probabilities for ungaged, and frequency of floods on natural-flow streams in Florida: unregulated streams in Florida. U.S. Geological Survey Water-Resources Investigations Multiple-regression techniques were used to define four 82–4012, 44 p., 1 pl. hydrologic regions having similar flood characteristics and to develop predictive equations relating peak flow to specified Cohn, T.A., Lane, W.L., and Stedinger, J.R., 2001, Confidence drainage-basin characteristics. The flood regions were delin- intervals for Expected Moments Algorithm flood eated based on plotted residuals, previous flood-frequency quantile estimates: Water Resources Research, v. 37, no. 6, studies, and geologic, physiographic, and drainage-area maps. p. 1695–1706. The most significant variable determined for predicting flood Dalrymple, Tate, 1960, Flood-frequency analyses—Manual of flows in Florida was drainage area, followed by storage. Gen- Hydrology: Part 3. Flood-flow techniques: U.S. Geological eralized least-squares regression methods were used to define Survey Water-Supply Paper 1543–A, 80 p. the regression coefficients used in the predictive equations and both the model and prediction errors. Feaster, T.D., Gotvald, A.J., and Weaver, J.C., 2009, The regional flood-frequency relations can be applied Magnitude and frequency of rural floods in the Southeastern to streams in Florida that are not significantly affected by United States, 2006—Volume 3, South Carolina: U.S. backwater, regulation, urbanization, or channelization. Meth- Geological Survey Scientific Investigations Report ods are presented in this report for determining flood flows 2009–5156, 226 p. for selected exceedance probabilities on ungaged and gaged streams. On large streams where the regional flood-frequency Florida Office of Cultural and Historical Programs, [undated], relations do not apply, flood flows for 50-, 20-, 10-, 4-, 2-, Florida Quick Facts, accessed August 30, 2005, at 1-, 0.5-, and 0.2-percent chance exceedance probabilities are http://dhr.dos.state.fl.us/facts/stats/quick/. estimated from graphical relations of flood flows and drain- Flynn, K.M., Kirby, W.H., Mason, R., and Cohn, T.A., 2006, age areas for the Apalachicola River and Suwannee River at Estimating magnitude and frequency of floods using the Ellaville and below. PeakFQ program: U.S. Geological Survey Fact Sheet 2006–3143, 2 p. Giese, G.L., and Franklin, M.A., 1996, Magnitude and Acknowledgments frequency of floods in the Suwannee River Water Management District, Florida: U.S. Geological Survey The authors gratefully acknowledge the peer reviews Water-Resources Investigations Report 96–4176, 14 p. from Tony Gotvald (USGS Hydrologist, Atlanta, Ga.) and Larry Bohman (USGS Southeast Regional Surface-Water Gotvald, A.J., Feaster, T.D., and Weaver, J.C., 2009, Specialist, Norcross, Ga.) whose contributions enhanced the Magnitude and frequency of rural floods in the southeastern scientific merit of this report. The technical advisement and United States, 2006—Volume 1, Georgia: U.S. Geological guidance from Scott Hedgecock (USGS Hydrologist, Mont- Survey Scientific Investigations Report 2009–5043, 120 p. gomery, Ala.) during the project and report compilation were invaluable. The design and layout of the plate was performed Griffis, V.W., Stedinger, J.R., and Cohn, T.A., 2004, by Katie Lee (USGS Civil Engineer, Montgomery, Ala.). Log-Pearson Type III quantile estimators with regional skew Assistance with the preparation of the appendixes was information and low outlier adjustments: Water Resources provided by Peter Nevels (USGS Hydrologic Technician, Research, v. 40, W07503, doi:10.1029/2003WR002697. Montgomery, Ala.). Appreciation is extended to Sandra Griffith, G.E., Omernik, J.M., and Pierson, S.M., 2008, Dickerson (USGS Hydrologic Information Assistant, Orlando, Ecoregions of Florida: U.S. Environmental Protection Fla.) for her assistance with the extensive preparation and Agency, accessed May 26, 2010, at http://www.epa.gov/ formatting of the data presented in this report. wed/pages/ecoregions/fl_eco.htm. Haan, C.T., 1977, Statistical methods in hydrology: Ames, Iowa State University Press, 378 p. 20 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
Hammett, K.M., and DelCharco, M.J., 2005, Estimating the Seijo, M.A., Giovannelli, R.F., and Turner, J.F., Jr., 1979, magnitude and frequency of floods for streams in west- Regional flood-frequency relations for west-central Florida: central Florida, 2001: U.S. Geological Survey Scientific U.S. Geological Survey Water-Resources Investigations Investigations Report 2005–5080, 15 p. plus apps. Open-File Report 79–1293, 41 p. Hedgecock, T.S., and Feaster, T.D., 2007, Magnitude and Stedinger, J.R., and Tasker, G.D., 1985, Regional hydrologic frequency of floods in Alabama, 2003: U.S. Geological analysis—Ordinary, weighted, and generalized least Survey Scientific Investigations Report 2007–5204, 28 p. squares compared: Water Resources Research, v. 21, no. 9, plus apps. p. 1421–1432. Helsel, R.M., and Hirsch, D.R., 1995, Studies in environ- Tasker, G.D., and Stedinger, J.R., 1989, An operational GLS mental science 49—Statistical methods in water resources: model for hydrologic regression: Journal of Hydrology, Amsterdam, Elsevier Science, 529 p. v. 111, p. 361–375. Pride, R.W., 1958, Floods in Florida, magnitude and fre- U.S. Geological Survey, 1999a, National elevation dataset: quency: U.S. Geological Survey Open-File Report U.S. Geological Survey Fact Sheet 148–99. FL–58002, 136 p. U.S. Geological Survey, 1999b, National hydrography dataset: Pride, R.W., and Crooks, J.W., 1962, The drought of 1954–56, U.S. Geological Survey Fact Sheet 106–99. its effect on Florida’s surface-water resources: Florida Geological Survey Report of Investigations 26, 65 p. U.S. Water Resources Council, 1976, Guidelines for determining flood-flow frequency: Washington, U.S. Rabon, J.W., 1971, Evaluation of streamflow-data program Government Printing Office, Bulletin 17. in Florida: U.S. Geological Survey Open-File Report FL–70008, 70 p. U.S. Water Resources Council, 1977, Guidelines for determining flood-flow frequency (revised): Washington, Ryberg, K.R., 2008, PFReports: A program for systematic U.S. Government Printing Office, Bulletin 17A, 25 p., checking of annual peaks in NWISWeb: U.S. Geological 14 apps. Survey Open-File Report 2008–1284, 17 p. U.S. Water Resources Council, 1982, Guidelines for deter- Sauer, V.B., 1974, Flood characteristics of Oklahoma mining flood-flow frequency (revised): Washington, U.S. streams—Techniques for calculating magnitude and Government Printing Office, Bulletin 17B, 28 p. 14 apps. frequency of floods in Oklahoma, with compilations of flood data through 1971: U.S. Geological Survey Water Resources Investigations Report 52–73, 307 p. Searcy, J.K., and Hardison, C.H., 1960, Double-mass curves: U.S. Geological Survey Water-Supply Paper 1541–B, p. 31–66. Appendixes and Supplemental Data 21
Appendixes and Supplemental Data
Data for gaging stations in Florida (modified from Hedgecock and Feaster, 2007).
The following appendix tables contain peak stage and discharge data for streamflow gaging stations in Alabama. The tables contain a brief description of the gage location, type of gage, gage datum (if known), drainage area in square miles, historical data and explanatory remarks. Elevations are referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29). The tables of peak stages and discharges show only the annual maximums. The qualifica- tion codes in the tables correspond to the peak data codes as used in the U.S. Geological Survey National Water Information System (NWIS). The following qualification codes apply to the discharge columns:
1 discharge is a maximum daily average; 2 discharge is an estimate; 4 discharge is less than indicated value, which is the minimum recordable discharge at this site; 5 discharge affected to unknown degree by regulation or diversion; 6 discharge affected by regulation or diversion; 7 discharge is an historic peak; A year of occurrence is unknown or not exact; B month or day of occurrence is unknown or not exact; E only maximum peak available for this year. The following qualification codes apply to the gage height columns: 1 gage height affected by backwater; 2 gage height not the maximum for the year; 3 gage height at different data or at different site and datum; 5 gage height is an estimate.
The following abbreviations apply to the tables: --, date or data not available; ft, feet; ft3/s, cubic feet per second; mi, mile; mi2, square miles.
The supplemental data for this report includes full descriptions of the streamgages used in this study, such as location, datum information, period of record, and any special remarks associated with the streamgage (historic flood information, for example). Additionally, the peak-flow data are included. These data are available online at https://pubs.usgs.gov/sir/2011/5034.
The drainage area data presented in appendixes 1 and 3 are those as defined by the use of GIS analysis for this project. The drainage area data presented in the supplemental data are those as historically derived and published in the National Water Information System (NWIS). 22 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 9770 6710 9340 1550 1710 1600 9230 5570 7380 1290 1570 1410 8240 6390 7850 43900 29400 37700 18500 10500 13500 60200 45500 56600 45700 17200 27400 0.5 1110 8560 5820 8220 1270 1330 1290 8370 7230 4390 5930 1030 1220 6700 5050 6400 33800 23600 30000 14000 10700 46300 36600 44300 33700 13700 22000 1 854 996 906 7660 5160 7390 1070 1090 1070 6930 8860 5900 3620 4950 5650 4160 5420 11200 11400 27300 19700 24800 37400 30700 36300 26200 18300 2 885 866 880 698 794 729 6770 4560 6560 8840 5630 7240 4720 2920 4050 9340 4680 3370 4510 21700 16200 20100 29700 25400 29100 20000 14900 4 717 675 708 560 618 577 5880 3940 5710 6790 4470 5760 3680 2310 3230 7450 3800 2660 3680 11800 16800 13000 15900 23000 20400 22700 14900 10 411 516 449 505 401 403 4700 3200 4600 9120 4550 3080 4020 2480 1570 2240 9430 5180 8050 2750 1820 2680 11300 10900 15700 14500 15600 377 306 367 295 279 292 20 3780 2640 3710 7900 6520 7710 3160 2160 2860 1710 1090 1570 6200 3670 5550 2020 1260 1970 11000 11000 10400 205 142 197 826 529 771 167 129 161 616 50 1130 1100 2440 1850 2420 4000 3370 3930 1600 1080 1480 5740 5480 5730 2840 1860 2650 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 46 42 26 24 50 21 27 26 27 record (years) Period of 0.30 0.65 1.00 0.60 0.50 0.90 2.20 1.70 43.3 Storage (percent) ) 2 1.98 1.66 44.87 14.96 18.47 105 (mi area 256.03 559.15 106.69 Drainage
Station name Sopchoppy, Fla. Sopchoppy, near Coolidge, Ga. 188) near Coolidge, Ga. near Moultrie, Ga. Road 111) Thomasville, Ga. Ga. Whigham, Ga. near Sopchoppy River near Tributary Ochlockonee River Ochlockonee River (State Road Little Ochlockonee River (State Ochlockonee River near Barnetts Creek near Meigs, Ga. Thomasville, Barnetts Creek near Popple Branch at State Route 179 Whigham, Ga. Creek near Wolf 229 230 231 232 233 234 235 236 237 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.
a a a a a a a a
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02327100 02327350 02327355 02327415 02327500 02327550 02327700 02327860 02327900 Appendix 1. [mi Appendix 1 23 80.3 574 656 273 682 387 316 109 0.2 1550 1060 1430 1260 5820 7080 6380 11900 39600 12500 26900 60800 67500 23600 16400 84100 54700 69400 115000 71.7 93.6 0.5 811 523 579 963 235 682 316 257 1100 9940 1200 9370 4440 5520 4890 28200 21000 49400 88700 53800 17900 12500 59600 41200 51200 65.2 82.3 1 486 976 525 654 883 768 209 551 268 217 8250 7700 9930 3590 4500 3930 21500 17000 41600 71600 44500 14200 45100 32700 40000 58.7 71.8 2 450 781 474 517 699 603 183 437 225 181 3110 6710 6240 7780 2860 3610 11100 16100 13500 34400 57000 36300 33400 25500 30600 52.2 61.9 4 414 609 427 398 540 461 159 338 187 147 5340 4940 8440 5960 2260 2830 2420 11800 10400 27700 44300 28900 24100 19400 22600 43.4 49.4 10 366 419 369 267 365 305 128 230 142 108 7450 3690 6920 3470 5620 4000 1590 1960 1680 19700 30500 20300 14800 12900 14300 36.4 81.0 40.1 112 328 296 326 184 253 207 105 160 20 1180 4930 2600 4700 2510 3860 2790 9480 8880 9370 1400 1220 14200 21700 14600 91.1 73.2 82.0 74.0 25.8 47.0 27.2 271 156 267 130 101 704 753 709 50 2370 1300 2300 7480 7640 1380 1940 1460 4220 4490 4250 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 11700 11 11 11 11 36 81 15 41 19 record (years) Period of - 2.00 1.73 0.41 0.00 0.10 0.24 1.10 0.00 2.90 (per cent) Storage ) 2 1.44 1.03 58.2 64.9 16.9 0.515 0.270 237 (mi area 1140 Drainage
Station name Havana, Fla. Fla. Tallahassee, Jamieson, Fla. Fla. Quincy, Fla. at Quincy, Fla. near Quincy, Fla. Tired Creek near Cairo, Ga. Tired Ochlockonee River near at Tributary Arm Megginnis near Tributary Attapulgus Creek Creek near Willacoochee Fla. Little River near Quincy, Quincy Creek at State Hwy 267 St. Matthews Church Branch Littman Branch near Quincy, 238 239 240 241 242 243 244 245 246 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
a
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02329000 02329180 02329354 02329490 02329500 02329534 02329558 02328000 02329559 Appendix 1. [mi 24 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 6270 8340 5440 7620 6410 9290 4640 2710 3680 9260 8670 9170 60700 81200 14800 26500 14500 27000 16400 23600 98800 103000 108000 132000 113000 123000 109000 0.5 4780 6250 4230 6080 5000 7270 3580 2350 3030 8030 7500 7960 81100 11200 72500 46000 60200 10000 85400 18700 20900 13300 18800 82900 97200 88600 103000 1 7370 3830 4960 3450 5050 4060 5940 9100 2900 2080 2570 7150 6640 7090 11200 54700 36600 47100 64400 83500 67600 14100 17000 15600 71500 80200 74800 2 5310 3010 3850 2780 4140 3250 4790 7270 9290 2320 1840 2150 6300 5960 6260 40500 28700 36100 50300 67200 52700 10400 13600 12700 60600 65600 62400 4 3740 2310 2910 2190 3320 2540 7570 3770 5650 7560 1820 1590 1750 5480 5060 5440 29100 22000 26800 38500 52800 40200 10700 10100 50100 52300 50800 10 7110 2220 1550 1900 1530 2380 1750 4690 2630 3850 7340 5570 1270 1280 1270 4440 4090 4410 17800 14700 17000 25900 37000 26800 36900 37600 37100 923 944 20 1110 5110 1400 1070 1280 1750 1240 3060 1890 2680 5210 4200 1050 3650 3370 3630 11100 11300 10200 18100 26700 18600 27300 27800 27400 628 547 609 616 665 520 732 539 50 5000 5220 5040 1000 9510 9710 1430 1030 1350 2760 2510 2740 2530 2360 2520 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 14800 14800 16000 15100 11 42 17 15 78 22 53 22 32 record (years) Period of - 0.46 0.09 3.19 2.84 1.49 6.66 5.25 35.11 43.03 (per cent) Storage ) 2 9.37 28.9 27.8 24.7 305 128 151 (mi area 1720 2100 Drainage
Station name Quincy, Fla. Quincy, Fla. Wetumpka, Bloxham, Fla. Greensboro, Fla. Creek, Fla. Little River near Midway, Fla. Little River near Midway, Rocky Comfort Creek near Ocklawaha Creek near Ochlockonee River near Creek near Telogia Creek near Bristol, Fla. Telogia Ochlockonee River near Smith Fla. Vilas, New River at New River near Sumatra, Fla. 247 248 249 250 251 252 253 254 255 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02329600 02329700 02329877 02330000 02330050 02330100 02330150 02330200 02330400 Appendix 1. [mi Appendix 1 25 0.2 134 596 223 942 1150 5680 2500 2180 2360 4780 4970 4810 11700 11600 33800 14700 21600 35600 20200 30200 16500 13600 44000 15800 27100 59200 30600 114 460 178 726 860 0.5 8910 3000 1980 1670 1850 4200 4120 4180 11700 26200 12400 18000 29600 17100 25700 10100 10400 35500 13600 21900 47500 24300 99.4 1 373 148 586 678 8920 7130 7970 9470 1780 1630 1340 1520 3760 3520 3720 11900 21300 10800 15600 25300 15000 22500 29700 18400 39600 20200 86.1 2 297 121 465 520 9100 6680 5610 6170 8520 1020 1320 1060 1230 3340 2980 3290 21100 17000 13100 12600 19200 24600 10400 15400 32700 16600 73.6 97.9 4 230 545 360 385 817 974 7480 4910 4310 4650 7540 8920 1050 2920 2470 2860 13200 10700 17100 10400 15800 20000 12600 26400 13400 57.9 71.3 10 157 210 244 237 743 551 689 9020 5630 7820 7890 3120 2900 3050 6190 7060 9460 9840 2360 1870 2310 11600 12200 14700 19300 46.5 53.7 87.3 109 170 145 539 382 502 20 6330 4220 5720 8740 5940 8390 2100 2010 2070 5100 5660 7310 7500 1930 1450 1890 11000 14500 297 195 280 903 30.9 56.0 33.0 16.8 87.0 51.3 50 3250 2340 3050 4370 3330 4250 1050 1030 1050 3430 6600 3690 4630 8570 4690 1300 1280 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 11 11 24 65 21 12 18 72 22 record (years) Period of
0.00 0.10 0.20 0.22 7.30 0.00 0.00 6.74 10.03 (per- cent) Storage ) 2 1.92 0.290 0.565 24.9 28.4 283 468 565 833 (mi area Drainage
Station name Tributary near Tributary Fla. Hardaway, Colquitt, Ga. Chattahoochee, Fla. Oakdale, Fla. Fla. Fla. Fla. South Mosquito Creek Spring Creek (U.S. 27) at Ga. Spring Creek near Iron City, Flat Creek near Chipola River at Mockingbird Run near Cypress, Altha, Holliman Branch near Altha, Fla. Chipola River near Sandy Creek near Panama City, 256 257 258 259 260 261 262 263 264 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
a a Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02356510 02358600 02358800 02358946 02358998 02359000 02359300 02356640 02357000 Appendix 1. [mi 26 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 — — — 0.2 2380 6520 2850 2380 8850 2750 4870 5490 8500 1480 4290 1870 2630 2040 14600 12200 10900 76900 80700 117000 101000 132000 217000 155000 — — — 0.5 2100 5380 2450 2180 7330 2460 4120 4550 9900 6970 8960 1270 3270 1540 2130 1660 11900 83700 74300 61600 65400 113000 168000 128000 1 — — — 1130 1900 4580 2160 2030 6260 2240 3620 3920 8370 5920 7660 2620 1320 1800 1400 10100 64300 58500 51600 55100 99700 136000 109000 2 — — — 988 1120 1160 1700 3870 1890 1870 5300 2030 3140 8430 3350 6990 4980 6470 2060 1490 48800 45600 42800 45900 86400 91600 108000 4 — — — 855 934 943 1500 3190 1640 1710 4390 1820 2710 6900 2840 5750 4100 5380 1580 1210 36400 35000 34900 37600 73600 84200 76000 10 — — — 686 720 878 700 1240 2410 1320 1480 3330 1550 2180 5140 2240 4290 3070 4070 1060 23800 23700 25800 27300 56900 58200 57200 559 732 572 650 539 20 — — — 1040 1850 1090 1300 2580 1340 1800 3910 1840 3290 2350 3160 16500 16600 19800 20500 44500 41500 43900 739 758 997 381 371 380 367 324 50 — — — 1150 1620 1010 1300 2390 1310 2030 1440 1980 8870 8910 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 12300 12400 27300 22500 26500 18 17 68 24 75 49 13 19 10 record (years) Period of - 9.38 8.29 8.69 6.80 6.30 2.20 0.00 0.00 11.24 (per cent) Storage ) 2 5.12 1.44 40.6 70.2 57.1 122 686 (mi area 1180 3180 Drainage
Station name Lake, Fla. Fla. Fla. Fla. Ala. Newton, Pittman, Fla. Ala. Fadette, Econfina Creek near Compass Econfina Creek near Fountain, Econfina Creek near Bennett, Youngstown, Bear Creek near Choctawhatchee River near Ala. Pea River near Samson, Choctawhatchee River near Fowler Branch near Leonia, Fla. near Tributary Grants Branch 265 266 267 268 269 270 271 272 273 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
b b b
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02359350 02359450 02359500 02359550 02365200 02365237 02361000 02364500 02365310 Appendix 1. [mi Appendix 1 27 — 0.2 1010 2150 1310 14200 18300 16000 32200 17400 24800 24100 33300 26000 22300 22300 22300 23100 20300 21700 55400 52600 180000 213000 188000 190000 212000 194000 — 0.5 820 1650 1030 11100 14800 12700 24000 14000 19500 19900 27000 21200 17100 16900 17000 18200 15800 17100 41300 42000 136000 165000 142000 152000 167000 154000 1 — 694 840 9200 1330 11600 12400 10400 19000 16000 17000 22600 18000 13800 13500 13700 14900 12800 14000 32900 35000 113000 108000 134000 127000 137000 128000 2 — 581 679 7520 8490 9580 1050 11000 11400 10300 86300 89300 14800 12900 14400 18900 15000 10600 10900 12100 10300 25900 28700 111000 108000 105000 106000 4 — 479 806 541 6060 8400 6780 7710 8590 8130 8470 9560 8030 8990 11300 11900 67900 84600 69700 10200 15300 12300 85600 88100 85800 20200 23300 10 — 357 543 386 4420 6190 4850 7640 5590 7160 8850 9090 5940 5460 5840 6700 5560 6340 11300 48400 59100 49100 63700 62800 63600 14100 16500 20 — 274 376 287 3340 4670 3590 5380 4160 5170 6710 8570 6860 4270 3780 4190 4830 3960 4600 11900 36500 42600 36800 49200 46000 49000 10400 50 — 169 192 171 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 2060 2790 2140 2900 2420 2860 3950 5160 4020 2360 1930 2320 2620 2130 2530 6350 6700 23300 23500 23300 31400 26200 31300 13 75 30 36 76 19 26 15 12 record (years) Period of - 6.73 2.92 4.67 7.87 4.69 0.00 0.29 1.35 5.70 (per cent) Storage ) 2 116 151 393 461 1.88 65.8 83.8 (mi area 3510 4380 Drainage
Station name Highway 177-A near Highway 177-A Fla. Bonifay, Caryville, Fla. Fla.. Bruce, Fla. Defuniak Springs, Fla. Fla. Wrights Creek at State Wrights Choctawhatchee River at Sandy Creek at Ponce De Leon, Fla. Vernon, Holmes Creek at Choctawhatchee River near Pate Branch near Freeport, Fla. Alaqua Creek near Alaqua Creek near Portland, Ala. Wing, River near Yellow 274 275 276 277 278 279 280 281 282 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
b
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02365470 02365500 02365700 02366000 02366500 02366859 02367000 02367006 02367800 Appendix 1. [mi 28 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 — 667 445 520 692 361 482 0.2 1200 4390 1620 59100 26500 15600 22500 63600 44400 58900 51200 69400 45100 31900 61900 26500 46400 164000 111000 103000 — 502 345 402 534 280 381 0.5 1040 3420 1330 21100 46700 83700 21200 12700 18400 49600 35500 46500 40100 80600 53000 32700 24200 45800 36100 113000 1 — 917 397 280 326 436 227 316 1130 2780 84500 38500 66600 17600 10700 15500 40500 29400 38400 33200 65700 42400 25100 19300 35800 17500 29500 — 2 804 956 309 223 259 351 185 260 2230 8900 61900 31300 51900 14400 12900 32700 24200 31400 27200 53000 33600 18900 15200 27600 14400 23600 — 4 211 697 800 235 173 201 280 141 1750 7250 11500 11800 11500 44400 24900 39200 10500 25900 19400 25100 22100 41700 26300 13800 20700 18400 96.0 10 — 118 561 614 154 137 200 157 1210 8090 5350 7580 8600 8000 8300 27300 17800 25600 18300 14000 17900 16500 29300 18400 13400 12500 — 83.0 95.8 67.0 460 857 488 105 150 122 20 5830 4050 5560 5540 5440 9090 6140 8680 17900 13000 17300 13400 10400 13200 12800 21200 13700 320 458 327 50 — 51.2 43.0 48.7 91.5 31.0 79.7 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 8590 7410 8520 3100 2430 3030 7720 6060 7660 8520 8710 2450 2500 4450 3550 4370 11800 11 11 66 18 34 68 18 36 52 record (years) Period of - 3.88 0.84 0.00 0.00 6.98 5.10 2.90 0.80 4.37 (per cent) Storage ) 2 7.75 0.190 0.140 87.7 624 123 474 206 (mi area 1220 Drainage
Station name Fla. near Tower near Caney Creek Paxton, Fla. near Paxton, Fla. Head, Fla. Ala. Bradley, Fla. Baker, Yellow River at Milligan, Fla. Yellow Baggett Creek near Milligan, No. 2 Tributary Caney Creek No. 1 Tributary Caney Creek Shoal River near Mossy Fla. Shoal River near Crestview, River near Holt, Fla. Yellow Blackwater River near Blackwater River near 283 284 285 286 287 288 289 290 291 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
b Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02368000 02368300 02368326 02368329 02368500 02369000 02369500 02370000 02369800 Appendix 1. [mi Appendix 1 29 — — — — 0.2 2720 4010 15100 13500 14000 85400 46000 69400 19600 17600 18300 14400 90100 91600 56000 46800 25500 20600 83400 63100 180000 253000 187000 — — — — 0.5 8320 2090 2980 11000 10300 10500 62000 35200 52300 12800 13500 13200 73200 74800 39800 34500 20800 16800 61000 48200 152000 194000 155000 1 — — — — 9110 8520 8300 8380 5340 1680 2330 47900 28300 41600 10900 10100 61800 63300 30400 27100 17700 14200 47700 38800 132000 157000 134000 — — 2 — — 6500 6570 6540 6360 8700 7470 3310 1330 1770 11900 36400 22400 32600 51500 52900 22800 21000 14900 36700 31000 113000 125000 114000 4 — — — — 4850 5070 4970 4330 6760 5320 1970 1030 1290 9860 27100 17300 24800 42100 43400 16700 16000 12300 27800 24500 95800 96800 95900 10 — — — — 896 697 775 3110 3140 3440 3280 2450 4630 9290 7520 11800 17400 16500 31000 31800 10600 10600 18600 17400 74400 66700 74000 439 485 462 20 — — — — 2140 2400 2240 8270 1490 3270 1880 7030 7130 7220 5970 11800 11300 23300 23700 13100 12600 58900 47400 58500 119 621 752 250 159 50 — — — — 1120 1080 1250 5830 4340 5720 1730 3440 3490 4610 3940 7180 7060 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 13800 13800 38200 25600 37800 10 60 27 23 58 67 12 37 73 record (years) Period of - 0.48 0.89 0.87 0.13 7.90 1.80 2.10 4.10 2.04 (per cent) Storage ) 2 2.85 34.5 58.7 79.4 240 176 330 (mi area 1340 3840 Drainage
Station name Fla. Milton, Fla. Milton, Fla. Ala. Andalusia, Ala. Evergreen, Ala. Robinsville, Ala. Flomaton, Fla. Century, Big Juniper Creek near Munson, Big Coldwater Creek near Pond Creek near Milton, Fla. Hurricane Branch near Conecuh River near Murder Creek near Sizemore Creek near Big Escambia Creek at Escambia River near 292 293 294 295 296 297 298 299 300 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
b b b b Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 02370200 02370500 02370700 02370750 02375500 02372500 02374500 02374970 02375000 Appendix 1. [mi 30 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 7160 5720 6310 68100 24400 43000 19400 13200 17200 67500 32200 57200 288000 248000 271000 0.5 5410 4380 4830 48200 18500 32500 15400 10400 13800 52800 26200 45800 220000 192000 209000 1 4320 3520 3890 8500 11500 36500 14800 26000 12700 43300 22000 38300 178000 156000 170000 2 3400 2780 3090 6870 9460 11600 27000 20300 10400 34900 18400 31500 143000 124000 137000 4 8880 2620 2150 2400 8260 5430 7620 19400 15400 97200 27600 15000 25300 113000 109000 10 5950 1780 1450 1650 5840 3820 5480 11100 11700 10000 80800 67600 78400 19300 18100 20 1180 7420 4120 6640 1260 1010 4240 2760 4020 8450 60700 48400 59100 14000 13300 679 519 645 50 3180 2100 3010 2330 1530 2240 7640 5130 7400 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 37600 26500 36800 42 26 13 34 66 record (years) Period of - 0.28 2.60 0.22 2.02 8.60 (per cent) Storage ) 2 8.81 74.7 52.2 394 (mi area 4150 Drainage
Station name Barth, Fla. Molino, Fla. Pensacola, Fla. Hill, Fla. Walnut Park, Fla. Pine Barren Creek near Escambia River near Carpenter Creek at Brushy Creek near Perdido River at Barrineau 301 302 303 304 305 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 1.—Continued
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom line, weighted estimates; —, no data] Type III distribution; middle line, regression equation estimates; bottom weighted —, , square miles; peak-flow data: top line, log-Pearson 2 Characteristics are from Hedgecock and Feaster, 2007. Characteristics are from Hedgecock and Feaster, Characteristics are from Gotvald and others, 2009. 02376000 02376033 02376079 02376300 02376500 a b Appendix 1. [mi Appendix 1 31 0.2 1160 5670 5120 7000 5550 3780 2950 3560 1460 1240 4960 2920 4080 1700 2140 1820 12900 10400 13200 10900 12400 61900 19700 46700 24200 32500 26100 0.5 4790 8670 4560 5900 4820 3230 2450 3060 9080 1030 1220 1070 3930 2420 3370 1430 1780 1510 11200 21100 10200 10500 47800 16600 38500 27300 22400 1 927 953 8390 4130 7380 4120 5060 4270 2840 2090 2690 9720 7740 9190 1050 3250 2070 2870 1240 1530 1300 38600 14300 32600 19000 23400 19800 2 829 879 838 1100 6780 3500 6160 3640 4260 3720 2460 1750 2350 8300 6470 7880 2650 1730 2410 1060 1280 30700 12000 27000 16900 19700 17300 4 730 724 729 893 914 2110 5350 2900 5000 3140 3520 3170 1440 2020 6930 5300 6630 9920 2120 1420 1980 1050 23800 21800 14900 16200 15100 10 598 529 590 686 767 694 3700 2130 3560 2420 2570 2430 1650 1040 1600 5190 3850 5000 7250 1510 1030 1440 11800 16000 15200 12400 12300 20 761 494 387 484 752 537 561 539 1110 2620 1560 2550 1840 1880 1840 1320 1280 3900 2800 3780 5290 1070 8610 11100 10700 10500 10300 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 847 985 987 850 415 827 339 212 329 622 410 608 338 306 336 1350 1320 1020 2190 1520 2130 5550 2860 5440 7740 4640 7610 11 63 38 27 23 80 30 13 23 record (years) Period of 8.02 5.86 7.38 64.4 23.3 27.4 19.8 18.5 13.4 Storage (percent) ) 2 9.36 21.0 20.0 15.0 131 126 156 707 (mi area 1360 Drainage
Station name River at Moniac, Ga. Fla. Taylor, River at Fla. Macclenny, River at Glen Fla. St. Mary, Fla. Macclenny, Boulogne, Fla. near Hilliard, Fla. Gross, Fla. Callahan, Fla. North Prong St. Marys Middle Prong St. Marys Creek at Turkey South Prong St. Marys St. Marys River near Pigeon Creek at River Little St. Mary’s St Marys River near Alligator Creek at 1 2 3 4 5 6 7 8 9 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02228500 02229000 02230000 02230500 02231000 02231230 02231250 02231253 02231268 Appendix 1. [mi 32 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 4190 8130 5560 4970 5330 2660 5770 3080 5090 3570 4570 4080 5670 4590 4250 4500 2010 3800 2560 4260 5300 4600 7040 4120 5240 11000 14300 0.5 3470 6700 4440 4170 4350 2290 4840 2580 4340 2990 3940 3380 9180 4490 3940 3550 3850 1590 2250 1780 3620 4410 3840 5120 3420 4190 10400 1 8070 2950 5640 3700 3580 3670 2020 4150 2220 3780 2570 3470 2890 7860 3700 3460 3040 3370 1310 1930 1450 3160 3760 3310 3950 2920 3450 2 6110 1170 2470 4670 3040 3010 3030 1750 3500 1880 3230 2160 3000 2430 6600 2990 2980 2550 2910 1060 1620 2730 3150 2820 3000 2440 2770 4 831 909 4500 2020 3730 2440 2480 2450 1480 2880 1550 2690 1780 2540 2010 5430 2360 2520 2100 2460 1330 2320 2580 2360 2220 2000 2150 10 573 966 614 1120 2110 1160 2820 1460 2540 1750 1810 1750 2000 1300 1910 1500 3960 1670 1910 1530 1870 1800 1870 1810 1420 1450 1420 20 856 878 953 403 706 426 945 962 1140 1120 1840 1070 1720 1280 1330 1290 1540 1480 1430 2890 1230 1450 1420 1420 1370 1420 1060 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 822 580 800 717 721 717 486 837 496 793 519 769 672 706 825 608 810 204 385 214 907 742 895 453 577 464 1560 40 27 51 30 24 30 32 15 25 record (years) Period of 4.55 7.07 6.70 11.4 24.2 24.4 24.9 15.0 14.6 Storage (percent) ) 2 30.5 72.9 93.0 43.2 46.9 20.7 51.7 33.8 219 (mi area Drainage
Station name Crawford, Fla. Korona, Fla. Seville, Fla. Springside, Fla. Bardin, Fla. Bardin, Fla. Hastings, Fla. Fla. near Camp Blanding, Fla. Thomas Creek near Middle Haw Creek near Little Haw Creek near Rice Creek near Etonia Creek at Simms Creek near Deep Creek near Deep Creek at Spuds, South Fork Black Creek 10 52 53 54 55 56 57 58 59 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02231280 02244320 02244420 02244473 02245050 02245140 02245255 02245260 02245400 Appendix 1. [mi Appendix 1 33 0.2 315 726 340 452 663 6300 3920 5000 1960 1880 1940 7680 3120 4960 8120 5190 6970 1260 1660 1290 1060 28100 10200 21600 25100 10700 21700 0.5 291 591 308 839 368 554 1180 1190 4740 3200 4000 8450 8930 1610 1570 1600 5610 2620 4050 6410 4270 5690 1360 22000 17800 21300 18900 1 273 499 284 693 310 478 1120 1150 1120 3780 2710 3330 7200 7630 1360 1340 1360 4360 2250 3400 5270 3620 4790 17900 15200 18400 16700 2 255 413 261 949 563 257 408 1130 1130 1130 2970 2240 2710 6020 6390 3330 1890 2780 4260 3020 3960 1060 1050 14400 12700 15700 14500 4 913 929 916 235 335 239 990 770 979 448 209 344 2290 1820 2160 4930 5250 2490 1560 2220 3360 2460 3200 11200 10300 13000 12300 10 650 678 653 208 240 209 891 824 889 316 150 260 1140 1560 1310 1520 7680 3570 7270 9630 3820 9250 1610 1520 2330 1770 2260 20 948 467 496 469 837 185 175 184 805 401 792 228 109 197 1120 1100 5370 2600 5180 7140 2780 6910 1090 1060 1660 1290 1620 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 112 614 516 607 239 271 241 540 456 534 865 700 855 146 146 657 219 644 124 96.0 60.0 2710 1410 2650 3860 1510 3750 25 67 76 43 33 39 19 13 12 record (years) Period of Period 0.18 5.49 9.28 17.2 28.7 1.51 0.00 0.00 0.00 Storage (percent) ) 2 136 177 14.9 13.3 36.7 31.6 3.51 (mi area 0.920 0.429 Drainage
Station name Farms, Fla. near Penney Farms, Fla. Fla. near Middleburg, Bayard, Fla. Durbin, Fla. Jacksonville, Fla. Cedar Hills, Fla. Jacksonville, Fla. at Jacksonville, Fla. Greens Creek near Penney South Fork Black Creek North Fork Black Creek Big Davis Creek at Durbin Creek near Ortega River at Creek at Williamson Mccoy Creek at Tributary Red Bay Branch 60 61 62 63 64 65 66 67 68 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02245470 02245500 02246000 02246150 02246200 02246300 02246460 02246497 02246522 Appendix 1. [mi 34 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 813 787 805 824 545 755 769 932 4350 2560 3370 3370 2680 3130 2020 2040 2030 1470 2660 1980 1890 1200 2270 5710 4610 5380 1380 0.5 695 660 685 692 984 496 642 639 756 1160 3280 2130 2730 2820 2240 2650 1790 1710 1770 1440 2220 1770 1380 1910 4720 3880 4510 1 609 567 598 594 821 456 561 549 996 636 2620 1820 2290 2430 1930 2300 1600 1470 1570 1410 1910 1610 1060 1640 4020 3340 3880 2 525 478 515 797 501 668 412 483 466 839 526 2070 1530 1880 2050 1620 1960 1400 1240 1380 1360 1600 1440 1390 3360 2820 3270 4 443 395 434 580 414 522 365 409 390 693 427 1180 1150 1600 1260 1510 1690 1340 1630 1200 1020 1290 1320 1300 2740 2330 2680 10 914 979 338 289 331 917 744 900 964 355 303 342 295 843 319 297 507 315 1100 1150 1130 1070 1230 1200 1970 1710 1950 20 789 668 775 906 717 887 259 212 254 691 545 678 983 705 969 223 223 223 236 618 254 232 372 240 1430 1250 1420 92.2 95.5 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 117 440 364 435 483 391 476 151 148 369 298 363 619 384 585 122 143 337 151 751 679 747 146 203 148 25 29 19 31 25 29 25 42 21 record (years) Period of Period 11.6 27.1 34.3 22.8 19.2 34.8 49.3 38.1 29.5 Storage (percent) ) 2 19.0 28.1 4.26 17.0 24.4 4.62 27.0 76.8 10.0 (mi area Drainage
Station name Dinsmore, Fla. Jacksonville, Fla. Jacksonville, Fla. Highway 207 near Augustine, Fla. St. Augustine, Fla. St. Summer Haven, Fla. Daytona Beach, Fla. Holly Hill, Fla. Ormond Beach, Fla. Trout River at Trout Pablo Creek at Cedar Swamp Creek near Moultrie Creek at State Moultire Creek near Fish Swamp Outlet near Bay Canal near Tiger River near Tomoka River near Tomoka Little 69 70 71 72 73 74 75 76 77 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02246600 02246828 02246832 02246900 02247000 02247200 02247480 02247510 02247600 Appendix 1. [mi Appendix 1 35 0.2 1600 2770 1660 2740 5470 8160 2450 4560 3940 7760 4550 6180 7160 4940 7590 11900 11300 13000 23500 33100 25400 42100 35200 39600 40300 40400 40300 0.5 1440 2330 1480 2270 4180 6100 2060 3840 3400 6480 3820 5160 9980 5860 3880 9280 5830 10800 20200 28100 21500 35100 29700 33400 35100 34100 35000 1 1320 2000 1350 1920 9250 3320 4810 1770 3290 3000 5640 3310 4440 8730 4960 3200 7830 4670 31100 17700 24700 18700 30100 25600 28900 29300 31000 2 1210 1690 1220 1590 7750 2550 3730 1490 2780 2600 4710 2810 3770 7320 4130 2600 6490 3630 15300 21000 16000 25300 21600 24500 27100 24700 26900 4 1080 1400 1090 1280 6350 1890 2820 1230 2280 2200 3850 2340 3150 6000 3390 2080 5260 2740 12800 17400 13200 20700 17900 20200 23000 20400 22900 10 914 916 887 902 1020 4610 1200 1840 1620 9600 9870 1680 2860 1760 2390 4500 2520 1500 3770 1820 13300 15100 13100 14800 17500 15000 17400 20 776 749 775 614 799 661 1150 1120 3360 1250 7180 7370 1280 2120 1330 1840 3360 1910 9550 2730 1270 11000 10100 10800 13200 10900 13100 50 559 408 557 282 365 607 361 581 738 761 661 708 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 1150 1120 1150 1820 3890 5770 4010 1850 5780 5140 5720 1480 7240 5870 7190 55 23 29 73 25 25 28 14 81 record (years) Period of 37.2 7.00 32.0 52.2 47.0 30.0 41.0 0.00 33.4 Storage (percent) ) 2 113 220 195 33.4 26.0 93.7 77.6 (mi area 2100 2430 Drainage
Station name Samsula, Fla. Bronson, Fla. Station, Fla. Ga. Fargo, Dupont, Ga. State Road 187 near Thelma, Ga. Benton, Fla. Fla. Valley, Suwannee Springs, Fla. Spruce Creek near River near Waccasassa Creek at Lebanon Tenmile Suwannee River at Suwanoochee Creek at Suwanoochee Creek at Suwannee River near Deep Creek near White Suwannee River at 78 183 184 185 186 187 188 189 190 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
a a a
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson 2 02248000 02313400 02314200 02315000 02315200 02315500 02314500 02314600 02314700 Appendix 1. [mi 36 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006
0.2 4170 35300 43300 36900 36500 37500 36600 16300 13400 15400 42900 42300 61300 48500 49000 30800 44500 29900 24000 29100 76700 55800 69800 18800 17600 18500 045000
0.5 11300 30200 36500 31200 30600 31800 30700 13700 13000 35700 37500 36300 34500 50700 38000 39000 25400 36200 25400 20200 24800 60300 46400 56300 14600 14000 14500 1 9840 11800 11300 11700 11900 26400 31400 27100 26400 28100 26600 31300 32000 31500 29200 43000 31800 32200 21700 30400 22100 17700 21700 49400 40000 47100 12000 2 9990 8270 9640 9640 9530 9630 22900 26400 23300 22400 23900 22500 27000 26800 27000 24300 35800 26100 26000 18100 24900 18900 14900 18600 39800 33600 38500 4 8200 6790 7960 7630 7610 7630 19400 21800 19600 18500 19800 18600 22800 22000 22700 19900 29200 21000 20500 14700 19900 15900 12300 15700 31300 27600 30700 10 5930 5100 5820 9250 5370 5290 5370 11900 15000 16000 15100 13700 15200 13800 17400 16000 17200 14700 21000 15200 14000 10800 13700 12000 21600 20400 21500 20 4290 3820 4230 9740 7900 9620 9200 6940 9120 3910 3750 3900 11700 11700 11700 11600 11600 11200 11400 10200 10200 13400 13100 15200 15200 15200 15200 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 2110 7230 6270 7190 5660 6630 5690 2170 2160 7830 6240 7640 6680 8180 6730 4730 4270 4710 5380 3890 5330 7850 8450 7890 2200 1900 2190 35 79 23 13 32 25 42 36 22 record (years) Period of Period 31.5 40.0 7.47 1.61 7.20 1.00 0.800 0.800 0.700 Storage (percent) ) 2 239 498 577 108 (mi area 2650 1340 1660 1720 1490 Drainage
Station name Suwannee Springs, Fla. Statenville, Ga. Statenville, Ga. Jennings, Fla. Fla. Jasper, Bemiss, Ga. Quitman, Ga. Berlin, Ga. Suwannee River at Alapaha River at Little River near Alapaha River near Alapaha River near River near Withlacoochee Adel, Ga. Little River near River near Withlacoochee Okapilco Creek near 191 192 193 194 195 196 197 198 199 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
a a a a a a
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02315550 02317620 02317630 02317500 02317600 02317748 02318000 02318500 02318600 Appendix 1. [mi Appendix 1 37 0.2 3920 5370 4320 8370 6920 7600 2800 3530 3020 21100 39000 30000 34100 62200 91500 10400 16700 34800 20200 30900 10700 10200 10600 94300 28300 35200 103000 0.5 3220 4520 3520 8700 6420 5700 6070 2300 2970 2470 9440 8490 9180 81100 30500 24100 27300 51600 74400 17900 14600 29100 17000 26400 64900 23700 29200 1 2730 3880 2950 7440 5160 4830 5020 1960 2550 2090 8480 7250 8170 25000 20100 22800 66700 43900 62400 15400 13000 24900 14500 23000 47300 20200 24600 2 2270 3280 2420 6240 4080 4020 4060 1650 2150 1740 7530 6080 7210 11300 20000 16500 18600 53800 36600 51300 13100 20900 12200 19600 33100 17000 20300 4 1830 2710 1930 5130 9590 3140 3280 3180 1360 1770 1420 6580 4990 6280 41100 15600 13300 14700 42400 30000 10700 17000 10100 16300 22100 14000 16200 10 2110 9310 1290 1980 1350 7680 3740 7100 7330 2360 2160 1020 1300 1050 5310 3630 5070 11700 11500 10600 10200 29300 21700 28800 12100 10200 10700 20 921 955 782 949 793 6110 7420 6660 7230 1450 5460 2730 5130 8580 5340 8390 1460 1720 1500 4320 2640 4120 7410 6790 20700 15700 20400 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 460 788 477 725 932 746 477 517 479 3700 3440 3650 8430 2620 1480 2500 4170 2880 4100 2850 1430 2720 1690 4000 2550 10600 10500 27 76 41 37 75 19 25 12 10 record (years) Period of 0.00 3.32 33.3 12.7 16.5 1.51 30.7 9.28 13.1 Storage (percent) ) 2 272 189 608 163 958 93.5 50.2 46.0 (mi area 2150 Drainage
Station name Road 33 near Quitman, Ga. Pinetta, Fla. Graham, Fla. Fla. Butler, Springs, Worthington Fla. Lulu, Fla. Fla. Butler, Providence, Fla. Highway 441 near High Springs, Fla. Okapilco Creek at State River near Withlacoochee Santa Fe River near New River near Lake Santa Fe River at Olustee Creek near Swift Creek near Lake Olustee Creek near Santa Fe River at U.S. 200 201 202 203 204 205 206 207 208 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
a
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson 2 02319000 02320700 02321000 02321500 02321600 02321700 02321800 02321975 02318700 Appendix 1. [mi 38 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 881 688 408 469 1910 1330 5130 3140 4220 8770 5180 6980 2890 6420 3460 3940 4900 30900 28400 30100 23400 29700 24200 16300 10500 14600 10600 0.5 718 490 335 376 1580 1050 8870 3760 2670 3340 6290 4390 5490 2500 5430 2890 3420 8830 4050 25600 23800 25100 19400 24900 20000 13300 12200 1 311 607 866 371 284 1340 7640 2920 2300 2720 4810 3780 4450 2200 4680 2490 3010 7560 3450 11200 21700 20400 21400 16700 21300 17100 10500 2 504 694 274 236 250 1120 2110 9250 6460 8820 2220 1950 2150 3620 3200 3500 1920 3960 2600 6340 2880 18100 17100 17900 14100 17900 14400 4 411 911 539 196 193 195 7480 5360 7230 1650 1620 1640 2660 2660 2660 1630 3280 1750 2190 5220 2360 11700 11900 14600 14100 14500 14700 10 118 298 658 368 139 127 1190 8720 8800 5340 3940 5230 1060 1070 1680 1950 1720 1260 2410 1320 1640 3800 1720 10300 10200 10300 10700 73.0 82.3 20 221 479 259 101 703 877 716 983 1120 1140 7300 7450 7310 6610 7780 6640 3870 2880 3810 1430 1770 1020 1210 2770 1260 29.7 56.0 35.3 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 124 262 139 334 478 341 543 778 553 589 959 602 632 658 3560 4020 3590 3860 4190 3860 2050 1560 2030 1500 11 41 10 75 56 51 49 32 56 record (years) Period of 2.53 1.60 12.3 62.8 99.3 74.3 64.0 13.5 13.0 Storage (percent) - ) 2 350 120 160 198 965 7.21 60.0 (mi 1020 0.530 Drain age area
Station name Gainsville, Fla. Alachua, Fla. White, Fla. Fla. Cross City, Fla. Foley, Fla. Foley, Perry Fla. Fla. Perry, Springs, Fla. Blues Creek near Bad Dog Branch near Santa Fe River near Fort Steinhatchee River near Fenholloway River near Fenholloway River at Fenholloway River near Econfina River near Santa Fe River near High 211 210 212 213 214 215 216 217 209 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02322016 02322049 02322500 02324000 02324400 02324500 02325000 02326000 02322000 Appendix 1. [mi Appendix 1 39 77.2 0.2 476 485 478 132 109 170 177 174 7120 8940 3190 3530 3420 4160 6790 5480 3330 1360 1890 15500 27000 23300 25300 13000 24700 16800 58.6 84.3 0.5 429 394 422 107 137 144 141 1110 6310 7610 2200 2900 2640 3260 5660 4330 2500 1550 13000 21700 19500 20800 10300 20700 13100 46.7 90.0 67.8 1 115 118 392 333 381 122 936 5700 6650 1630 2460 2100 2670 4840 3540 8600 1980 1310 11100 17900 16700 17500 17700 10700 36.6 75.0 52.9 94.6 97.2 2 354 276 341 101 775 1180 1100 5090 9300 5740 2040 1600 2160 4050 2810 7080 8520 1540 14400 14100 14300 14900 27.9 61.0 39.6 75.9 82.0 78.0 4 821 315 224 302 629 893 1160 1160 4480 7640 4880 1660 1710 3330 2160 5750 6640 11100 11600 11200 12300 18.3 44.0 25.0 53.8 59.0 55.2 10 473 676 259 160 248 753 451 635 3650 5560 3840 1200 1200 2420 1440 7210 8430 7390 4230 8940 4640 12.4 32.0 16.2 38.8 43.0 39.7 20 117 284 869 397 872 213 204 504 328 451 2990 4050 3080 1770 1000 4650 6140 4820 3220 6510 3410 6.00 7.44 64.0 18.0 20.4 24.0 21.0 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 109 474 150 483 958 527 141 135 235 179 224 2020 2190 2030 1820 3310 1960 2000 3510 2050 11 11 11 17 12 15 41 23 13 record (years) Period of 12.1 9.95 0.00 15.5 15.5 0.00 0.00 0.00 0.940 Storage (percent) ) 2 353 748 822 15.4 87.0 2.54 (mi area 0.480 0.059 0.095 Drainage
Station name Aucilla, Fla. Cherry Lake, Fla. Greenville, Fla. Monticello, Fla. Lamont, Fla. Scanlon, Fla. near Monticello, Fla. Miccosukee, Fla. Monticello, Fla. Aucilla River near Aucilla River near Little Aucilla River near Little Palmer Mill Branch at Aucilla River at Aucilla River near Tributary Creek Ward Halls Run near Caney Creek near 218 219 220 221 222 223 224 225 226 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Station number , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson 2 02326250 02326261 02326300 02326372 02326500 02326512 02326574 02326595 02326598 Appendix 1. [mi 40 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 6890 2820 3640 7100 8160 21600 0.5 4770 2310 2930 6240 6960 18000 1 6110 3550 1960 2440 5610 15400 2 2600 1620 1980 4980 5300 12900 4 1860 1320 1570 4350 4540 10600 10 949 1130 1060 3510 7690 3610 20 724 689 715 2860 5590 2910 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 332 376 339 1900 3020 1920 14 48 record (years) Period of 0.55 8.40 Storage (percent) ) 2 530 9.78 (mi area Drainage
Station name Miccosukee Rd Tallahassee, (No. 28) Fla. Newport, Fla. Lafayette Creek, St. Marks River near 227 228 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 2.—Continued
Characteristics are from Gotvald and others, 2009. Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson a number 2 02326838 02326900 Appendix 1. [mi Appendix 1 41 408 585 931 0.2 4480 2690 3670 2460 4750 2580 1320 3070 1540 2310 1210 1690 1070 1370 1080 22000 17900 20800 22600 20600 22500 18700 21700 19000 0.5 992 344 888 466 780 881 1120 1140 3910 2240 3230 2180 3930 2260 2540 1270 1780 1390 19600 15300 18500 20300 17600 20100 17700 18500 17800 1 972 838 297 754 383 667 975 738 1180 3470 1920 2910 1990 3350 2040 2160 1080 1440 17800 13400 16800 18500 15400 18300 16800 16200 16800 2 839 905 695 982 251 628 308 555 816 602 1140 3020 1610 2580 1790 2820 1820 1810 11600 16000 15200 16600 13300 16500 15900 14100 15800 4 714 751 888 560 796 207 509 242 446 665 474 2570 1320 2250 9800 1600 2310 1610 1480 11300 14200 13500 14800 14700 14900 12000 14800 10 604 395 567 150 361 166 306 476 319 957 558 573 1950 1770 7450 1340 1670 1340 1060 8620 9140 11600 11200 12300 12200 13500 13300 20 117 424 281 408 109 258 207 343 215 698 446 768 452 1130 1130 1470 1360 9570 5720 9280 1220 6640 7050 10300 10200 12200 12000 50 56.1 58.4 87.7 90.8 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 803 369 764 829 653 829 295 403 296 220 141 216 131 177 6460 3360 6320 7190 3930 7160 9890 4190 9800 17 13 71 45 73 26 12 27 48 record (years) Period of 30.8 26.8 16.6 20.4 25.6 27.8 25.8 41.0 43.90 Storage (percent) ) 2 35.4 43.0 68.1 (mi area 115 140 188 2480 2960 3240 Drainage
Station name Osteen, Fla. Sanford, Fla. Sanford, Fla. Cassia, Fla. Deland, Fla. Barberville, Fla. Fla. Astor, near Eva, Fla. Clermont, Fla. Deep Creek near St. Johns River near River near Wekiva Blackwater Creek near St. Johns River near Deep Creek near St. Johns River at Green Swamp Run Big Creek near 28 29 30 31 32 33 34 35 36 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02234100 02234500 02235000 02235200 02236000 02236120 02236125 02236350 02236500 Appendix 1. [mi 42 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 816 531 658 433 562 538 0.2 3110 1640 2760 2190 9340 3630 5960 6250 9300 9670 2280 3190 2730 3740 1820 2740 1850 3420 2230 11900 10500 0.5 671 435 554 293 425 396 1360 2310 1780 2790 7920 3140 5400 8880 5580 8240 8460 1860 2630 2190 3010 1460 2400 1550 2760 1800 10100 1 566 366 478 210 337 304 1160 1990 1490 2540 6890 2790 4970 7720 5080 7450 8790 7580 1550 2240 1810 2530 1220 2000 1340 2300 1500 2 464 302 403 968 145 260 223 992 1140 1680 1210 2290 5910 2450 4520 6640 4590 6650 7560 6720 1260 1870 1450 2100 1720 1890 1240 95.2 4 195 155 786 944 367 242 329 783 954 984 1120 1710 1460 1510 1000 1380 2040 4960 2130 4060 5580 4100 5840 6370 5870 1520 48.4 82.8 10 248 168 231 553 646 652 726 123 541 704 728 1130 1010 1680 3720 1720 3420 4190 3430 4760 4790 4760 1090 1250 1050 25.0 79.0 43.0 20 118 166 158 390 739 441 429 792 472 946 378 882 531 745 541 1390 2810 1410 2880 3180 2890 3900 3640 3890 6.60 50 11.1 34.0 69.9 57.0 68.7 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 566 186 545 304 378 306 188 395 205 938 944 174 415 190 1600 2040 1820 2150 2620 2090 2610 11 25 12 38 59 37 23 20 31 record (years) Period of Period 0.180 6.98 5.56 43.0 39.2 31.0 30.4 28.3 18.6 Storage (percent) ) 2 0.410 14.7 18.5 41.2 (mi area 112 185 1020 1200 1370 Drainage
Station name Clermont, Fla. Mascotte, Fla. Ocala, Fla. Fla. Conner, Eureka, Fla. Gainesville, Fla. Fla. near Micanopy, Gainesville, Fla. Arredondo, Fla. Little Creek near Palatlakaha River near Ocklawaha River near Ocklawaha River near Ocklawaha River at Prairie Creek near Tributary Moores Pond Hogtown Creek near Hogtown Creek near 37 38 39 40 41 42 43 44 45 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02236700 02237000 02239000 02240000 02240500 02240902 02240950 02240954 022409424 Appendix 1. [mi Appendix 1 43 461 397 442 435 930 587 0.2 3800 1750 2700 4430 8310 5290 4020 3560 3890 3710 3640 3700 29100 13600 15000 13700 15500 14100 14200 13500 14100 0.5 412 319 388 361 765 462 3010 1430 2270 3620 6940 4210 3280 2910 3190 3080 2990 3060 11500 11800 11500 19200 12500 13200 12100 12900 12700 1 375 265 350 305 647 375 2480 1210 1950 9900 3050 5960 3460 2760 2460 2700 2640 2520 2620 11500 11800 11600 13300 10500 10500 10700 10100 2 311 995 336 215 251 536 294 2000 1650 8600 8450 8490 2520 5050 2790 9250 9950 9340 8730 2290 2040 2250 2220 2100 2210 10800 10500 4 295 169 274 198 432 223 800 1860 1660 1830 1830 1700 1820 1570 1360 5100 7070 6420 2020 4190 2180 8050 8420 8080 9580 7400 9380 10 114 238 223 132 304 142 561 986 1180 1340 1320 1360 1210 1350 1080 2090 5270 3640 1410 3080 1490 6530 6380 6520 7900 5630 7770 78.0 85.8 91.6 20 754 399 712 819 997 192 181 980 846 974 872 216 3970 1870 2290 1040 5400 4880 5380 6500 4310 6400 1020 1010 36.0 33.2 35.2 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 116 375 201 364 104 371 490 502 122 537 440 535 579 454 576 108 2260 1270 3810 2850 3790 4280 2520 4230 28 20 58 22 16 25 47 48 60 record (years) Period of 11.6 11.9 21.2 35.0 16.0 16.6 17.0 27.3 35.8 Storage (percent) ) 2 4.63 37.4 85.0 90.7 29.3 (mi area 470 1010 2010 2100 Drainage
Station name Grove Park, Fla. near Citra, Fla. Orange Springs, Fla. Orange Springs, Fla. Kenwood, Fla. Riverside Lake near Orange Springs, Fla. Fla. Taft, Airport near Kissimmee, Fla. Fla. Vineland, Lochloosa Creek at Orange Lake Outlet Orange Creek at Ocklawaha River near Bruntbridge Brook at Ocklawaha River at Boggy Creek near Shingle Creek at Cypress Creek at 46 47 48 49 50 51 87 88 89 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02241900 02242451 02243000 02243500 02243530 02244000 02262900 02263800 02264000 Appendix 1. [mi 44 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 157 213 165 192 502 260 666 813 0.2 1960 1530 1870 3030 4810 3220 3740 1810 2950 1330 1210 2760 1620 2410 4560 2720 20800 12900 17800 0.5 140 166 143 164 410 209 549 649 1100 1740 1260 1660 2700 3980 2820 2950 1500 2450 1030 2280 1310 2200 3580 2370 11000 16900 15000 1 128 134 129 143 345 174 468 928 538 900 1110 1570 1070 1500 2460 3390 2530 2430 1280 2100 9560 1950 2040 2920 2130 14200 13000 2 116 115 106 890 122 284 141 393 771 438 778 915 1400 1340 2220 2840 2260 1970 1070 1760 8240 1630 1850 2340 1900 11700 11000 80.0 4 112 105 103 721 101 226 875 324 623 350 661 745 1180 1220 1980 2330 1990 1560 1450 9440 6950 9040 1330 1660 1830 1670 90.1 52.0 88.4 74.1 78.7 10 511 973 946 157 628 240 441 250 515 959 551 1100 1640 1680 1650 1060 6700 5250 6560 1370 1240 1360 78.7 34.0 77.4 53.7 56.0 20 110 773 366 755 800 454 780 181 315 185 408 697 423 852 1110 1120 1380 1230 1380 4830 4000 4780 50 61.9 15.0 61.3 26.8 53.0 27.5 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 474 187 465 984 655 980 441 235 436 105 159 106 262 366 265 718 416 710 2530 2320 2520 20 40 36 40 46 37 39 16 30 record (years) Period of 6.65 0.470 28.0 15.4 39.6 35.2 29.0 29.3 24.8 Storage (percent) ) 2 0.585 51.9 12.4 84.6 43.0 14.3 (mi area 117 180 1610 Drainage
Station name S-101a at Buena Fla. Vista, Fla. Vineland, Campbell, Fla. Fla. Vineland, near Fla. Vineland, Loughman, Fla. below Lake Kissimmee near Fla. Wales, Lake Frostproof, Fla. Park, Fla. Avon near Black Lake Outlet at Bonnet Creek near Shingle Creek at Whittenhorse Creek Reedy Creek near Davenport Creek near Kissimmee River Livingston Creek near Hole Creek Morgan 90 91 92 93 94 95 96 97 98 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02264051 02264100 02264495 02266200 02266300 02266480 02269000 02269520 02269720 Appendix 1. [mi Appendix 1 45 611 886 574 691 626 0.2 7220 2350 2880 2460 3600 3500 3580 1490 5010 3690 4330 1570 3750 1920 7020 6600 6920 4690 7810 5360 12000 10600 0.5 531 724 460 568 502 9610 6020 8760 1980 2390 2040 3240 3000 3200 1230 3870 3060 3510 1400 3120 1640 5660 5510 5630 3960 6530 4410 1 470 612 382 481 415 7990 5170 7450 1700 2030 1750 2950 2620 2900 1050 3140 2620 2940 1280 2660 1440 4740 4740 4740 3440 5610 3760 2 409 874 506 309 334 1150 6540 4370 6220 1440 1700 1470 2640 2260 2600 2510 2200 2420 2230 1260 1290 3910 4010 3920 2950 4760 3160 4 348 709 409 243 320 260 5240 3620 5070 1200 1390 1210 2320 1900 2280 1970 1800 1930 1020 1830 1080 3160 3320 3170 2480 3940 2610 10 884 997 890 266 505 295 842 868 165 225 174 3730 2650 3670 1840 1420 1820 1370 1300 1360 1320 2280 2430 2280 1900 2900 1950 20 113 118 659 724 661 203 363 217 981 949 979 700 965 710 159 2720 1960 2700 1450 1070 1440 1680 1800 1680 1480 2150 1500 52.7 79.0 54.1 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 115 119 363 380 364 856 597 847 186 537 504 534 484 513 485 947 948 948 907 912 1190 1500 1080 1500 67 57 35 13 25 16 25 66 33 record (years) Period of 17.4 22.4 91.0 32.7 21.2 20.9 44.2 19.8 18.1 Storage (percent) ) 2 58.0 23.0 (mi area 114 386 624 160 163 378 454 Drainage
Station name De Soto City, Fla. De Soto City, Fla. De Soto City, Cornwell, Fla. Canal near Dundee, Fla. Canal near Alturas, Fla. Canal near Fla. Wahneta, Eloise, Fla. Fla. Bartow, Fort Meade, Fla. Arbuckle Creek near Josephine Creek near Istokpoga Canal near Peace Creek Drainage Peace Creek Drainage Peace Creek Drainage Lulu Lake Outlet at Peace River at Peace River at 99 111 110 100 105 106 107 108 109 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02270500 02271500 02272000 02293694 02293986 02293987 02294068 02294650 02294898 Appendix 1. [mi 46 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 890 982 0.2 1640 2560 1840 4050 1430 2510 8370 5050 6270 2870 7040 6920 7010 1920 2160 2040 4330 1620 2840 4140 1590 2140 16800 10400 14900 0.5 838 898 1140 1430 2100 1550 3000 2040 6410 4100 5090 2310 5630 5620 5630 8460 1540 1740 1630 3470 1310 2420 3220 1260 1770 13400 12200 1 937 796 838 2110 1270 1770 1350 2350 1710 5120 3450 4260 1930 4700 4720 4700 7150 1280 1440 1340 2880 1090 2580 1030 1500 11100 10300 2 757 753 779 892 827 1120 1160 1180 1100 1460 1800 1410 4000 2850 3490 1580 3880 3910 3890 9030 5950 8560 1050 2330 1810 2000 1250 4 969 991 594 707 721 845 935 870 709 645 1180 1120 1340 3020 2300 2760 1260 3160 3160 3160 7200 4850 6940 1820 1510 1480 1010 10 773 835 777 850 402 770 641 873 645 604 645 612 490 889 434 690 1940 1620 1860 2320 2240 2320 5090 3470 4990 1230 1090 20 622 597 621 558 277 526 583 615 584 443 451 444 839 344 772 528 297 450 1160 1270 1250 1760 1610 1760 3690 2530 3640 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 407 306 404 251 133 245 547 604 552 485 309 484 847 246 223 245 382 170 365 172 141 166 1080 1080 2000 1360 1990 21 42 21 14 56 67 15 33 17 record (years) Period of 4.88 6.02 5.70 4.72 4.62 6.13 9.69 2.94 13.5 Storage (percent) ) 2 9.23 7.29 58.3 82.0 32.0 21.7 20.6 (mi area 110 205 Drainage
Station name Fort Meade, Fla. Socrum, Fla. above Crystal Springs near Zephyrhills, Fla. S-582 near Knights, Fla. Knights, Fla. Fla. Zephyrhills, near Mcintosh Road near Antioch, Fla. Sulphur Springs, Fla. Fla. Darby, Bowlegs Creek near Fox Branch near Hillsborough River Itchepakesassa Creek at Blackwater Creek near Hillsborough River Baker Creek at Creek near Trout Cypress Creek near 112 153 154 155 156 157 158 159 160 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02295013 02301900 02301990 02302260 02302500 02303000 02303205 02303350 02303358 Appendix 1. [mi Appendix 1 47 781 373 440 418 576 493 537 846 637 0.2 1100 2880 2420 2640 3960 3210 3660 4560 3810 4290 1080 1090 6910 2470 3730 8720 2670 6040 0.5 529 296 345 316 461 375 869 894 878 437 678 503 2170 1980 2090 3180 2650 3000 3800 3170 3610 5450 2020 3160 6780 2190 5070 1 378 243 278 252 382 297 724 748 731 370 562 415 3110 1710 1670 1690 2630 2260 2520 3250 2700 4490 1710 2760 5510 1850 4360 2 259 194 216 197 309 229 589 612 595 309 456 337 1300 1390 1330 2130 1890 2080 2720 2270 2630 3640 1420 2400 4390 1540 3680 4 952 991 168 151 158 151 242 170 464 487 468 253 359 269 1120 1150 1680 1540 1650 2200 1860 2150 2890 2060 3400 1240 3000 82.6 89.9 10 811 574 791 605 100 100 164 109 315 337 318 882 188 245 193 1110 1140 1140 1560 1350 1540 2030 1600 2300 2140 40.9 68.0 48.9 69.4 72.8 20 112 348 566 368 782 805 784 983 215 236 217 582 633 143 169 145 1100 1090 1460 1250 1580 1520 9.60 31.0 12.6 35.1 53.0 35.7 97.5 98.3 87.0 81.0 86.8 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 116 125 290 132 365 423 367 522 524 522 796 299 736 776 326 761 11 44 41 43 21 26 37 62 24 record (years) Period of 11.0 11.1 15.0 20.1 21.1 13.6 15.2 15.6 15.0 Storage (percent) ) 2 2.26 5.47 8.31 58.8 17.1 62.7 68.9 (mi area 122 168 Drainage
Station name San Antonio, Fla. San Worthington Gardens, Fla. near Sulphur Springs, Fla. near Lutz, Fla. Dyke Rd near Citrus Park, Fla. River near Odessa, Fla. Odessa, Fla. Elfers, Fla. Springs, Fla. Tarpon Cypress Creek near Cypress Creek at Cypress Creek Lake Magdalene Outlet Van Brooker Creek at Anclote South Branch Anclote River near Anclote River near Hollin Creek near 161 162 163 164 165 166 167 168 169 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02303400 02303420 02303800 02306289 02307200 02309848 02309980 02310000 02310147 Appendix 1. [mi 48 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 4110 1710 2380 2140 3860 6370 4800 4120 2040 2890 4870 3530 4480 5190 8430 6200 9740 1760 2710 4690 1970 3340 7750 11100 11300 12500 10400 0.5 1240 1930 1640 2890 5240 3600 3150 1700 2400 4300 2970 3980 9990 4360 7230 9120 5240 8260 3430 1460 2390 3810 1650 2890 9520 6570 8890 1 941 1630 1290 2280 4450 2820 2510 1460 2030 3850 2560 3590 8250 3760 6320 7730 4540 7160 2910 1250 2140 3170 1420 2540 8200 5700 7760 2 683 955 1340 1760 3720 2140 1940 1230 1680 3390 2170 3190 6670 3200 5420 6420 3880 6070 2400 1040 1870 2580 1200 2180 6910 4890 6640 4 468 663 852 984 1080 1320 3040 1560 1450 1010 1320 2900 1790 2770 5220 2650 4500 5200 3240 5000 1890 1580 2020 1790 5670 4090 5520 10 611 854 954 907 733 874 713 250 755 349 1120 2180 2230 1310 2160 3540 1950 3240 3700 2410 3620 1250 1350 1260 4100 3060 4040 20 569 614 573 535 568 971 801 442 750 894 521 858 132 537 183 1590 1700 1660 2420 1450 2300 2650 1800 2620 2970 2300 2940 33.6 46.8 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 265 851 276 226 282 230 934 525 918 797 295 229 289 375 274 370 272 1120 1100 1350 1010 1340 1510 1300 1510 44 35 39 29 76 40 48 67 32 record (years) Period of 9.69 11.1 44.8 38.3 30.2 34.8 37.0 48.0 33.6 Storage (percent) ) 2 85.0 43.0 182 130 267 390 595 132 819 (mi area Drainage
Station name River near New Port Fla. Richey, near Eva, Fla. River near Cumpressco, Fla. Fla. near Dade City, Fla. Trilby, River near Fla. Tarrytown, River at Rerdell, Fla. Croom, Fla. Loyce, Fla. Pithlachascotee River Withlacoochee Withlacoochee River Withlacoochee River at Withlacoochee Withlacoochee Little Withlacoochee Little River at Withlacoochee Jumping Gully at 171 172 173 174 175 176 177 178 170 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02310300 02310800 02310947 02311500 02312000 02312180 02312200 02312500 02310240 Appendix 1. [mi Appendix 1 49 562 648 586 0.2 8870 8030 8920 11500 15000 12200 12800 15900 13300 0.5 484 522 493 7510 9820 6900 7520 11000 12200 10400 10700 13500 1 426 434 427 6530 8560 6060 9010 6490 9170 9430 11700 10300 2 369 353 367 8390 5590 7310 5230 7750 5520 7760 7940 10100 4 314 279 310 6610 4690 6020 4410 6530 4590 6420 8540 6540 10 243 190 238 4460 3510 4260 3340 4910 3420 4780 6450 4830 20 189 131 185 2990 2650 2940 2530 3740 2570 3600 4920 3630 50 63.0 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 115 113 1280 1500 1300 1420 2150 1430 2080 2860 2090 23 24 40 75 record (years) Period of 31.1 16.6 27.8 23.6 Storage (percent) ) 2 8.00 939 (mi area 1400 1810 Drainage
Station name near Floral City, Fla. near Floral City, Sumterville, Fla. Dam at Wysong Carlson, Fla. Fla. near Holder, Withlacoochee River Withlacoochee Shady Brook near R at Withlacoochee River Withlacoochee 179 180 181 182 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 3.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02312600 02312667 02312720 02313000 Appendix 1. [mi 50 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 7110 1180 2330 5770 2690 6480 6650 1240 1210 4330 3140 3730 3870 3290 3570 4310 7910 27600 13000 21700 25400 21800 24600 10100 15600 27300 17200 0.5 970 996 2100 4700 2350 5690 5810 5720 1020 3460 2580 3050 3080 2670 2880 7820 3500 6370 20800 10600 17200 20700 17900 20100 14000 22300 15000 1 818 861 839 5110 1920 3960 2100 4910 5060 2880 2180 2580 8930 2550 2250 2420 6340 2950 5330 16500 14100 17400 15100 17000 12700 18900 13400 2 672 718 694 1730 3290 1850 4540 4090 4430 2360 1810 2140 7440 2090 1870 2000 5050 2440 4390 11400 11400 11700 12800 14300 12700 14100 15800 4 535 584 557 1530 2670 1610 3980 3330 3840 1900 1480 1750 9730 6060 8920 1680 1510 1610 3930 1970 3500 9860 11500 11400 10300 12900 10100 367 422 389 10 1160 1250 1930 1290 3240 2420 3080 1360 1070 1270 6400 4420 6070 8120 7600 8060 1200 1080 2680 1420 2480 7720 9520 7830 20 251 306 273 994 779 935 886 789 858 1010 1410 1040 2670 1780 2500 4350 3250 4200 5780 5630 5770 1880 1030 1770 5940 7060 6010 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 113 647 771 657 973 163 133 554 422 521 505 427 485 977 562 926 1840 1470 2120 1800 2080 2930 3140 2950 3270 3960 3330 11 29 10 14 53 60 12 50 53 record (years) Period of 7.9 6.77 10.6 18.1 31.6 20.9 15.9 29.0 29.9 Storage (percent) ) 2 8.60 52.6 30.2 17.4 24.6 105 258 905 (mi area 1330 Drainage
Station name Sunshine State Parkway near Fort Drum, Fla. near Fellsmere, Fla. Kenansville, Fla. Fla. Holopaw, Deer Park, Fla. Melbourne, Fla. Deer Park, Fla. Park, Fla. Cocoa, Fla. Fort Drum Creek at Blue Cypress Creek Creek near Wolf Crabgrass Creek near Jane Green Creek near St. Johns River near Pennywash Creek near Creek near Deer Wolf St. Johns River near 11 12 13 14 15 16 17 18 19 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02231342 02231396 02231458 02231565 02231600 02232000 02232155 02232200 02232400 Appendix 1. [mi Appendix 1 51 912 638 810 0.2 1190 1100 6820 2930 4730 2830 2740 3400 2860 3540 6940 2850 2600 2730 16300 29100 17300 16200 13600 15800 17100 35600 18400 4140 816 800 522 640 0.5 5180 2400 3830 2330 1020 2380 2780 2440 3170 5650 3590 2240 2090 2180 11000 14700 23800 15300 13500 13100 15600 29100 16500 1 739 885 618 441 524 4160 2020 3210 1970 2100 2350 2140 2890 4760 3200 9300 1850 1740 1800 11600 11300 13400 20200 13800 14400 24600 15000 2 656 758 468 366 420 3300 1680 2670 1650 1820 1950 1840 2610 3960 2810 9750 7750 9540 1500 1430 1480 12000 16900 12200 13200 20600 13600 4 569 639 346 296 324 1150 1180 2560 1370 2160 1340 1540 1580 1540 2320 3210 2450 8050 6300 7900 1200 11900 10500 13800 10700 16900 12200 10 986 445 974 487 218 212 216 860 813 847 1160 1140 1160 1770 1560 8470 8530 1930 2330 1990 5960 4590 5860 10200 10200 12400 10200 20 719 343 712 374 143 153 146 876 834 873 637 587 626 1150 1270 6760 7540 6790 1620 1700 1630 4470 3370 4400 8680 9230 8710 50 65.2 81.0 69.1 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 704 389 649 192 385 214 478 452 475 933 373 316 362 1110 1140 4150 4230 4160 2550 1870 2500 6340 5200 6280 25 71 29 20 47 10 71 25 15 record (years) Period of 0.750 11.0 16.2 29.5 34.1 15.8 14.6 12.7 27.4 Storage (percent) ) 2 1.83 3.80 22.7 35.3 27.1 72.9 (mi area 240 1470 1950 Drainage
Station name Christmas, Fla. Christmas, Fla. at Magnolia Ranch near Bithlo, Fla. near Tributary Bithlo, Fla. River near Union Park, Fla. River at State Road 434 near Oviedo, Fla. near Chuluota, Fla. Lake Harney near Geneva, Fla. Heather Glen Creek at Melbourne, Fla. Jim Creek near St. Johns River near Econlockhatchee River Econlockhatchee River Little Econlockhatchee Little Econlockhatchee Econlockhatchee River St. Johns River above Eau Gallie River at 20 21 22 23 24 25 26 27 79 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02232450 02232500 02233001 02233102 02233200 02233475 02233500 02234000 02249007 Appendix 1. [mi 52 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 1830 3770 2310 3350 5660 3960 4140 5770 3900 7100 4230 6610 3350 4830 6790 8230 11700 13800 14200 12400 13300 27500 16200 24800 44300 47900 45300 0.5 1560 3050 1900 2770 4560 3200 3680 4870 3520 5740 3730 5200 2730 3950 8630 5520 6540 11100 11800 11000 10000 22000 13200 20200 36700 39100 37400 1 1360 2550 1610 2390 3820 2700 3320 9290 4240 3230 4820 3370 4250 2310 3330 8470 9420 6730 4650 5410 11100 10200 18400 17100 31300 33100 31700 2 1160 2100 1340 2030 3150 2240 2960 7680 3640 2940 3980 3020 3400 1920 2770 8550 7050 7940 9230 5160 3860 4400 15000 14100 26100 27700 26400 4 969 1690 1090 1710 2540 1850 2600 6200 3090 2640 3210 2690 3650 1560 2220 7020 5720 6520 7510 3870 3130 3460 11400 12000 21200 22600 21400 722 796 10 1130 5110 1320 1820 1380 2100 4460 2400 2240 2310 2240 1780 1560 4160 4780 8370 5470 8090 2500 2260 2390 1210 15000 16700 15300 20 823 540 876 590 1100 1040 1320 1080 1710 3270 1910 1900 1690 1890 1220 3740 3060 3510 5960 4030 5800 1690 1650 1670 10700 12400 10900 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 690 720 693 923 575 446 537 827 904 853 295 475 325 1120 1810 1220 1380 1350 1980 1690 1880 3070 2240 3000 5290 7020 5550 11 11 11 18 20 20 75 35 20 record (years) Period of 2.22 2.52 3.71 8.6 2.25 11.0 16.4 12.1 23.2 Storage (percent) ) 2 20.8 95.5 39.4 28.5 60.0 10.8 (mi area 311 188 2830 Drainage
Station name Highway 1 at Melbourne, Fla. Fla. Palm Bay, Sebastian River near Sebastian, Fla. Sebastian Creek near Micco, Fla. Fla. Venus, Palmdale, Fla. near Okeechobee, Fla. Myers, Fla. Melbourne, Fla. Crane Creek at U.S. Creek near Turkey South Prong St. North Prong Saint Fisheating Creek near Fisheating Creek at Kissimmee R at S-65e Orange River near Fort Crane Creek at 81 82 83 84 85 86 80 102 103 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02249518 02250000 02251000 02251500 02256000 02256500 02273000 02293000 02249500 Appendix 1. [mi Appendix 1 53 0.2 1110 4880 7440 5860 5770 4660 5160 4320 1470 8390 5790 8220 6320 11500 10400 10800 36800 27900 34600 18400 12700 17700 18100 17800 61000 41500 55800 0.5 970 3840 6040 4600 4480 3780 4120 8100 9290 8470 3450 1230 6850 4900 6630 5240 28300 22700 27100 13900 10200 13700 14700 13900 46400 33700 43500 1 865 3170 5090 3770 3650 3180 3430 6610 7810 6950 2870 1060 5790 8460 4280 5560 4510 11000 11200 11400 22900 19200 22200 12400 37300 28400 35600 2 762 897 2580 4220 3030 2940 2640 2810 5300 6480 5590 2350 8480 4830 6910 8960 9160 3680 4590 3820 18300 16000 17900 10300 29500 23600 28600 4 661 757 3110 2060 3420 2390 2330 2130 2250 4150 5250 4380 1880 6360 3930 5430 7070 8370 7230 3710 3190 14300 13000 14200 23000 19200 22500 530 584 10 1470 2480 1660 1650 1530 1610 2830 3800 2990 1330 9510 9960 4080 2860 3700 4980 6090 5070 2390 2660 2430 10000 15900 14100 15700 20 430 963 464 1120 1190 1080 1810 1200 1220 1980 2780 2100 7240 7040 7230 2680 2100 2520 3640 4490 3690 1870 1940 1880 11400 11400 10400 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 621 994 671 709 608 688 285 522 302 1160 1190 1160 1150 1000 1540 1070 4080 3940 4080 1200 2070 2500 2100 6410 5890 6380 1070 18 13 32 21 74 26 57 77 24 record (years) Period of Period 8.6 6.4 6.1 0.00 9.76 2.90 12.8 19.0 10.5 Storage (percent) ) 2 5.92 70.0 27.1 44.0 116 790 142 326 (mi area 1330 Drainage
Station name Buckingham near Fort Myers, Fla. Punta Gorda, Fla. Bowling Green, Fla. Fla. Wauchula, Springs, Fla. Crewsville, Fla. Fla. Gardner, Arcadia, Fla. near CR760-A Nocatee, Fla. Orange River at Alligator Creek near Payne Creek near Thompson Branch near Peace River at Zolfo Charlie Creek near Charlie Creek near Peace River at Hawthorn Creek at 113 114 115 116 117 118 119 104 105 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02293050 02293400 02295420 02295630 02295637 02296260 02296500 02296750 02297088 Appendix 1. [mi 54 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 0.2 8400 6090 7390 8500 6150 7580 9170 11600 15500 15300 15500 19700 14800 20700 15400 19200 28700 15800 21800 12700 14100 19200 14900 26800 10300 17300 10100 0.5 6440 4930 5850 9400 7220 7660 8370 7550 4940 5980 11800 12100 12400 12100 14700 16400 12500 15400 21900 12800 17400 10300 12100 15600 12600 19400 13700 1 9860 5190 4140 4820 7910 9660 6310 8700 6610 7050 5900 4130 4900 9960 11500 11300 10400 13400 10500 12800 17600 10800 14500 10600 13100 10900 15100 2 7930 8590 8030 4120 3430 3910 8790 6560 7750 8740 8950 5450 7250 5650 9170 5850 9240 4500 3400 3930 11900 11500 10900 10500 13900 10900 13600 4 6260 6940 6350 3200 2770 3090 6460 5320 5980 8540 7090 8320 7260 9440 4630 5900 4750 7790 8890 7900 8600 4750 7280 3310 2730 3040 10700 10 4380 5010 4440 2190 1990 2150 3970 3850 3930 5890 5140 5800 7160 5270 6610 3610 4300 3660 6000 6480 6040 5600 3440 5050 2040 1940 2000 20 4110 3180 3670 3210 1550 1460 1530 2480 2830 2590 4140 3780 4960 3870 4680 2860 3160 2880 4670 4780 4680 3830 2520 3570 1280 1410 1330 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 822 795 818 980 514 771 599 1140 2110 1760 2040 1780 1560 2100 2100 2490 2150 2420 1830 1750 1830 2840 2660 2820 1970 1390 1880 57 29 23 57 22 34 36 33 18 record (years) Period of 3.21 5.13 7.23 7.12 7.28 8.81 0.870 14.4 10.4 Storage (percent) ) 2 36.8 16.4 129 130 206 217 233 373 121 (mi area Drainage
Station name Nocatee, Fla. Myakka Head, Fla. Limestone, Fla. Arcadia, Fla. Nocatee, Fla. Fort Ogden, Fla. Gorda, Fla. Fla. Myakka City, Sarasota, Fla. Joshua Creek at Horse Creek near Horse Creek near Horse Creek near Horse Creek near Prairie Creek near Shell Creek near Punta Myakka River at Howard Creek near 120 121 122 123 124 125 126 127 128 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
Station , square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson number 2 02297100 02297155 02297251 02297310 02297320 02298123 02298202 02298608 02298760 Appendix 1. [mi Appendix 1 55 548 985 0.2 2980 1060 3060 1430 2930 3280 3120 4770 6970 9910 8070 11600 11900 19000 15100 18000 10900 16900 13500 15100 13400 19500 16600 37000 12300 0.5 440 807 929 2270 2500 1200 2320 2680 2510 7740 3880 5460 9300 8010 9590 6520 9820 11200 14600 12300 14100 10400 12000 10900 15800 13600 25100 1 366 683 834 2110 1810 1050 1910 2260 2080 5840 3270 4450 9050 7770 8360 6720 9180 8050 5480 8150 11800 11500 11500 10300 10000 13200 18300 2 299 573 742 897 9400 8600 9280 1400 1760 1530 1880 1690 4310 2710 3540 6740 6390 6570 8200 5560 7630 6660 9680 4530 6680 10900 13100 4 238 460 651 763 1190 7340 6980 7290 1050 1430 1530 1330 3100 2200 2720 4920 5140 5010 6580 4490 6190 8770 5380 7900 9040 3660 5260 911 10 669 166 327 531 595 799 1100 5050 5070 5050 1030 1880 1590 1780 3080 3680 3280 4700 3240 4490 6240 3890 5740 5200 2630 3620 20 119 432 229 438 752 476 542 805 633 1190 1160 1180 3610 3730 3610 2040 2680 2210 3450 2370 3320 4530 2850 4200 3150 1920 2480 50 62.0 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 311 181 107 302 406 315 248 436 518 630 542 991 1170 1960 2070 1960 1480 1080 1930 1300 1860 2420 1570 2260 1260 1060 70 10 10 12 27 20 40 27 13 record (years) Period of 8.87 0.00 9.40 0.79 3.84 4.03 4.01 16.5 16.0 Storage (percent) ) 2 0.200 24.7 27.1 35.6 45.0 69.5 95.9 50.8 (mi area 229 Drainage
Station name Sarasota, Fla. River near Fla. Venice, at Power Line near North Port, Fla. near North Port Charlotte, Fla. Fla. Myakka City, Sarasota, Fla. Myakka Head, Fla. Bradenton, Fla. Parrish, Fla. Myakka River near to Myakka Tributary Deer Prairie Slough Deer Prairie Slough Big Slough Canal near Phillippe Creek at Manatee River near Manatee River near Gamble Creek near 129 130 131 132 133 134 135 136 137 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02298830 02298928 02299120 02299160 02299410 02299800 02299950 02300000 02300018 Appendix 1. [mi 56 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 537 529 537 764 618 0.2 810 802 5110 7260 7060 7200 2320 2720 1870 2050 1970 2290 1360 1740 5910 5310 1830 2280 1910 30900 13600 24900 472 672 466 444 620 502 0.5 668 6050 5690 5940 1860 2200 1410 1660 1541 1830 1090 1410 4060 4800 4220 1560 1850 1600 11000 23400 19700 1 423 576 418 575 380 520 423 909 1120 1190 5200 4760 5080 1550 1850 1390 1250 1520 3360 4030 3490 1360 1560 1390 9250 18700 16200 2 373 485 371 487 321 428 351 874 744 984 991 1140 1170 1180 4410 3930 4290 1270 1530 1220 2750 3340 2840 1290 7670 14700 13200 4 323 406 324 410 266 344 286 664 920 767 958 595 786 976 983 3660 3160 3550 1020 1240 2210 2700 2280 1040 6210 11300 10400 256 721 306 260 884 313 199 243 209 436 654 509 644 419 548 732 745 733 10 2760 2270 2660 1590 1950 1630 7530 4500 7140 20 203 520 238 210 642 247 152 175 157 296 473 348 436 301 381 550 541 549 2110 1190 1650 2030 1420 1200 5220 3310 5010 50 91.6 92.0 91.6 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 904 126 279 145 137 346 157 143 253 171 195 160 181 694 777 699 304 291 303 1260 1200 2650 1830 2570 19 14 14 13 14 14 44 46 68 record (years) Period of 2.12 0.400 5.11 3.22 2.27 0.44 6.37 6.71 6.27 Storage (percent) ) 2 2.70 9.75 0.940 3.99 1.14 8.58 29.3 39.9 (mi area 154 Drainage
Station name Lorraine, Fla. Creek near Lorraine, Fla. University Parkway near Sarasota, Fla. Sarasota, Fla. Sarasota, Fla. Bradenton, Fla. River near Fort Lonesome, Fla. Manatee River near Duette, Fla. Fla. Wimauma, near Braden River near Hickory Hammock Cooper Creek at Cedar Creek near Rattlesnake Slough near Nonsense Creek near Little Manatee South Fork Little Little Manatee River 138 139 140 141 142 143 144 145 146 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02300032 02300034 02300037 02300038 02300039 02300100 02300200 02300500 023000355 Appendix 1. [mi Appendix 1 57 0.2 1380 1470 1420 6520 9480 5870 7130 6160 2360 5330 3050 13700 10700 16900 14500 55600 16000 34200 0.5 1130 1160 1200 5270 8490 7710 4720 5830 4950 2080 4260 2570 11700 10400 13300 37700 13000 26200 1 960 982 1020 8260 4420 7000 6500 9800 3950 4930 4130 1870 3550 2220 11000 10900 27700 20900 2 806 846 820 4110 6460 3650 5680 8760 5400 8060 3250 3380 1650 2910 1890 9160 20000 16440 4 667 686 673 4940 2940 4470 6880 4380 6430 2610 3340 2710 1420 2320 1590 7450 14200 12400 502 494 500 10 1110 2110 3280 3070 4730 3180 4470 1860 2430 1920 1650 1200 8560 5430 8020 20 858 917 388 358 381 1190 2260 1540 2150 3330 2330 3210 1350 1780 1390 5520 4000 5340 50 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 840 733 978 754 496 649 528 243 192 233 1130 1090 1700 1280 1650 2620 2220 2580 11 47 54 44 14 74 record (years) Period of 2.89 9.96 0.00 17.8 19.7 12.8 Storage (percent) ) 2 7.81 8.36 30.0 (mi area 111 114 317 Drainage
Station name Wimauma, Fla. Wimauma, Alafia River at Keysville, Fla. River near Lithia, Fla. Hopewell, Fla. Lithia, Fla. Wimauma, Fla. Wimauma, Bullfrog Creek near North Prong Alafia South Prong Alafia River near Little Alafia River at Cypress Creek near 148 149 150 151 152 147 Map number Flood-frequency estimates using PeakFQ version 5.2 for Region 4.—Continued
, square miles; peak-flow data: top line, log-Pearson Type III distribution; middle line, regression equation estimates; bottom weighted estimates] , square miles; peak-flow data: top line, log-Pearson Station number 2 02300700 02301000 02301300 02301350 02301500 02300530 Appendix 1. [mi 58 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.2% ance 0.0111 0.0094 0.0158 0.0226 0.0236 0.0175 0.0237 0.0243 0.0204 0.0192 0.0236 0.0127 0.0276 0.0249 0.0230 0.0250 0.0203 0.0173 0.0230 0.0288 0.0254 0.0152 0.0268 0.0164 0.0249 chance exceed- G 0.2% 0.1134 0.0131 0.0306 0.0728 0.0850 0.0376 0.0865 0.0952 0.0547 0.0466 0.0855 0.0169 0.0208 0.1771 0.1051 0.0780 0.1074 0.0538 0.0367 0.0775 0.2405 0.0283 0.1506 0.0330 0.1045 ance chance exceed- W 0.0118 0.0112 0.0211 0.5% 0.0067 0.0174 0.0183 0.0131 0.0184 0.0189 0.0156 0.0145 0.0182 0.0081 0.0092 0.0218 0.0194 0.0178 0.0194 0.0154 0.0129 0.0177 0.0229 0.0198 0.0122 0.0194 ance chance exceed- G 0.0116 0.0711 0.0090 0.0210 0.0500 0.0582 0.0258 0.0594 0.0653 0.0375 0.0320 0.0579 0.0140 0.1216 0.0720 0.0532 0.0714 0.0368 0.0252 0.0529 0.1620 0.0774 0.0192 0.1020 0.0226 0.5% ance chance exceed- W 1% 0.0116 0.0050 0.0092 0.0141 0.0149 0.0103 0.0150 0.0155 0.0124 0.0148 0.0061 0.0069 0.0182 0.0160 0.0144 0.0158 0.0123 0.0102 0.0143 0.0192 0.0163 0.0086 0.0175 0.0096 0.0159 ance chance exceed- G 0.1145 1% 0.0064 0.0152 0.0361 0.0419 0.0186 0.0429 0.0471 0.0270 0.0232 0.0412 0.0084 0.0099 0.0879 0.0519 0.0382 0.0499 0.0265 0.0182 0.0380 0.0555 0.0137 0.0725 0.0163 0.0509 ance chance exceed- W, weighted using equation] W, W 2% 0.0110 0.0117 0.0118 0.0115 0.0112 0.0112 0.0036 0.0069 0.0078 0.0122 0.0096 0.0088 0.0045 0.0050 0.0148 0.0127 0.0123 0.0095 0.0077 0.0156 0.0129 0.0063 0.0140 0.0072 0.0126 ance chance exceed- G 2% 0.0113 0.0045 0.0100 0.0250 0.0289 0.0128 0.0299 0.0326 0.0186 0.0161 0.0279 0.0058 0.0067 0.0610 0.0358 0.0262 0.0330 0.0183 0.0126 0.0260 0.0770 0.0380 0.0094 0.0491 0.0350 ance chance exceed- W 4% 0.0117 0.0025 0.0050 0.0082 0.0088 0.0056 0.0090 0.0093 0.0070 0.0065 0.0086 0.0032 0.0034 0.0097 0.0084 0.0091 0.0069 0.0056 0.0083 0.0122 0.0098 0.0044 0.0108 0.0051 0.0096 ance chance exceed- Region 1 G 4% 0.0030 0.0071 0.0166 0.0191 0.0085 0.0201 0.0216 0.0123 0.0108 0.0179 0.0039 0.0042 0.0407 0.0237 0.0171 0.0204 0.0121 0.0085 0.0170 0.0488 0.0248 0.0060 0.0315 0.0075 0.0235 ance chance exceed- W 10% 0.0016 0.0032 0.0055 0.0059 0.0035 0.0063 0.0064 0.0045 0.0043 0.0055 0.0020 0.0018 0.0085 0.0066 0.0055 0.0057 0.0045 0.0037 0.0054 0.0087 0.0012 0.0026 0.0073 0.0032 0.0069 ance chance exceed- G 0.0018 0.0042 0.0095 0.0106 0.0047 0.0120 0.0122 0.0069 0.0063 0.0094 0.0024 0.0022 0.0234 0.0133 0.0093 0.0099 0.0067 0.0051 0.0092 0.0249 0.0013 0.0032 0.0164 0.0042 0.0143 10% ance chance exceed- W 0.0013 0.0025 0.0043 0.0046 0.0026 0.0052 0.0050 0.0034 0.0033 0.0040 0.0016 0.0012 0.0070 0.0052 0.0041 0.0040 0.0033 0.0029 0.0041 0.0068 0.0051 0.0018 0.0056 0.0023 0.0590 20% ance chance exceed- G 20% 0.0115 0.0014 0.0032 0.0066 0.0073 0.0032 0.0090 0.0085 0.0047 0.0046 0.0060 0.0018 0.0013 0.0166 0.0091 0.0062 0.0059 0.0046 0.0038 0.0062 0.0155 0.0089 0.0021 0.0104 0.0029 ance chance exceed- W 0.0012 0.0024 0.0039 0.0041 0.0022 0.0051 0.0046 0.0029 0.0031 0.0033 0.0015 0.0009 0.0069 0.0048 0.0035 0.0031 0.0028 0.0028 0.0035 0.0061 0.0046 0.0014 0.0049 0.0020 0.0063 50% ance chance exceed-
0.0110 0.0115 0.0014 0.0028 0.0054 0.0057 0.0025 0.0080 0.0068 0.0037 0.0040 0.0044 0.0016 0.0009 0.0138 0.0072 0.0047 0.0040 0.0036 0.0035 0.0047 0.0068 0.0015 0.0076 0.0023 G 50% ance chance exceed-
Variance of prediction values for gaging stations used in Florida regional regression analyses. Variance no. Map (pl. 1) 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253
no. USGS station 02327100 02327350 02327355 02327415 02327500 02327550 02327700 02327860 02327900 02328000 02329000 02329180 02329354 02329490 02329500 02329534 02329558 02329559 02329600 02329700 02329877 02330000 02330050 02330100 02330150 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; Appendix 2 59 - W ex 0.2% ance 0.0114 0.0112 0.0211 0.0118 0.0211 ceed- 0.0234 0.0218 0.0228 0.0134 0.0269 0.0180 0.0316 0.0236 0.0138 0.0139 0.0098 0.0083 0.0195 0.0183 0.0148 0.0162 0.0259 0.0257 0.0168 0.0230 0.0154 0.0225 0.0250 0.0283 0.0208 chance G 0.0112 0.1211 0.0830 0.0175 0.0659 0.0751 0.0226 0.1536 0.0402 1.0192 0.0850 0.0170 0.0239 0.0243 0.0140 0.0482 0.0415 0.0269 0.0599 0.0319 0.1251 0.0344 0.0777 0.0291 0.0186 0.0596 0.0727 0.1060 0.2140 0.0576 0.2% ance chance exceed- W 0.0114 0.0181 0.0083 0.0168 0.0176 0.0097 0.0212 0.0135 0.0257 0.0181 0.0080 0.0102 0.0103 0.0070 0.0058 0.0147 0.0135 0.0108 0.0161 0.0120 0.0203 0.0201 0.0121 0.0177 0.0085 0.0161 0.0173 0.0195 0.0224 0.0158 0.5% ance chance exceed- G 0.5% 0.0115 ance 0.0563 0.0120 0.0452 0.0516 0.0153 0.1030 0.0273 0.6996 0.0568 0.0164 0.0167 0.0096 0.0075 0.0328 0.0275 0.0182 0.0410 0.0219 0.0859 0.0812 0.0221 0.0524 0.0200 0.0124 0.0407 0.0494 0.0727 0.1396 0.0385 chance exceed- W 1% 0.0116 0.0146 0.0063 0.0135 0.0142 0.0074 0.0175 0.0106 0.0220 0.0149 0.0060 0.0078 0.0079 0.0053 0.0043 0.0105 0.0083 0.0129 0.0094 0.0168 0.0164 0.0090 0.0142 0.0089 0.0063 0.0129 0.0139 0.0160 0.0186 0.0124 ance chance exceed- G 1% 0.0119 0.0401 0.0087 0.0326 0.0372 0.0109 0.0726 0.0195 0.5050 0.0420 0.0082 0.0121 0.0069 0.0053 0.0235 0.0192 0.0129 0.0295 0.0158 0.0621 0.0572 0.0149 0.0371 0.0144 0.0087 0.0292 0.0352 0.0524 0.0954 0.0270 ance chance exceed- W, weighted using equation] W, W 2% 0.0111 0.0114 0.0117 0.0110 0.0046 0.0105 0.0054 0.0140 0.0080 0.0186 0.0043 0.0058 0.0059 0.0039 0.0030 0.0088 0.0077 0.0060 0.0100 0.0070 0.0135 0.0130 0.0064 0.0066 0.0045 0.0099 0.0108 0.0127 0.0148 0.0094 ance chance exceed- G 2% 0.0110 0.0273 0.0060 0.0225 0.0258 0.0074 0.0485 0.0134 0.3499 0.0290 0.0055 0.0083 0.0084 0.0048 0.0035 0.0161 0.0126 0.0088 0.0205 0.0431 0.0382 0.0094 0.0250 0.0100 0.0058 0.0200 0.0240 0.0362 0.0613 0.0180 ance chance exceed- W 4% 0.0113 0.0085 0.0032 0.0078 0.0084 0.0038 0.0106 0.0058 0.0153 0.0088 0.0029 0.0042 0.0042 0.0027 0.0019 0.0064 0.0052 0.0042 0.0075 0.0050 0.0104 0.0097 0.0041 0.0081 0.0048 0.0030 0.0073 0.0080 0.0097 0.0067 ance chance exceed- G 4% 0.0112 0.0176 0.0040 0.0149 0.0172 0.0049 0.0305 0.0089 0.2327 0.0192 0.0035 0.0056 0.0056 0.0032 0.0022 0.0105 0.0077 0.0056 0.0138 0.0073 0.0289 0.0240 0.0054 0.0159 0.0067 0.0036 0.0131 0.0155 0.0240 0.0364 ance chance exceed- W 0.0054 0.0019 0.0051 0.0056 0.0024 0.0071 0.0039 0.0121 0.0060 0.0016 0.0026 0.0026 0.0017 0.0010 0.0040 0.0029 0.0024 0.0051 0.0032 0.0074 0.0063 0.0020 0.0051 0.0030 0.0016 0.0046 0.0051 0.0067 0.0073 0.0039 10% ance chance exceed- - G ex 10% ance 0.0011 ceed- 0.0092 0.0022 0.0083 0.0098 0.0030 0.0153 0.0055 0.1321 0.0108 0.0018 0.0033 0.0033 0.0019 0.0057 0.0037 0.0029 0.0083 0.0041 0.0167 0.0120 0.0023 0.0082 0.0039 0.0018 0.0071 0.0082 0.0135 0.0163 0.0056 chance W 0.0011 0.0040 0.0014 0.0040 0.0044 0.0021 0.0053 0.0032 0.0107 0.0046 0.0021 0.0020 0.0013 0.0006 0.0029 0.0019 0.0016 0.0042 0.0023 0.0060 0.0046 0.0012 0.0036 0.0023 0.0010 0.0034 0.0037 0.0053 0.0052 0.0026 20% ance chance exceed- G 20% 0.0011 0.0060 0.0016 0.0057 0.0069 0.0025 0.0094 0.0044 0.0922 0.0074 0.0012 0.0025 0.0024 0.0014 0.0007 0.0038 0.0022 0.0018 0.0064 0.0029 0.0120 0.0074 0.0013 0.0051 0.0028 0.0047 0.0053 0.0093 0.0092 0.0034 ance chance exceed- W 0.0117 0.0033 0.0012 0.0034 0.0040 0.0022 0.0044 0.0034 0.0042 0.0008 0.0019 0.0018 0.0012 0.0004 0.0024 0.0013 0.0012 0.0042 0.0020 0.0058 0.0038 0.0008 0.0029 0.0021 0.0007 0.0029 0.0031 0.0048 0.0042 0.0020 50% ance chance exceed-
0.0044 0.0013 0.0046 0.0056 0.0026 0.0065 0.0045 0.0749 0.0059 0.0008 0.0022 0.0020 0.0013 0.0004 0.0028 0.0015 0.0013 0.0060 0.0023 0.0101 0.0052 0.0008 0.0037 0.0024 0.0008 0.0036 0.0039 0.0074 0.0060 0.0023 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
no. USGS station 02330200 02330400 02356510 02356640 02357000 02358600 02358800 02358946 02358998 02359000 02359300 02359350 02359450 02359500 02359550 02361000 02364500 02365200 02365237 02365310 02365470 02365500 02365700 02366000 02366500 02366859 02367000 02367006 02367800 02368000 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; 60 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.2% ance 0.0281 0.0274 0.0186 0.0141 0.0245 0.0231 0.0193 0.0292 0.0191 0.0277 0.0299 0.0126 0.0192 0.0242 0.0226 0.0083 0.0229 0.0233 0.0272 0.0187 0.0143 0.0122 0.0154 0.0134 0.0170 0.0127 0.0167 0.0176 0.0158 0.0157 chance exceed- G 0.0111 0.2020 0.1696 0.0431 0.0248 0.0986 0.0790 0.0473 0.2728 0.0462 0.1831 0.3531 0.0204 0.0466 0.0932 0.0736 0.0767 0.0812 0.1629 0.0437 0.0254 0.0219 0.0354 0.0264 0.0448 0.0236 0.0428 0.0491 0.0373 0.0369 0.2% ance chance exceed- W 0.5% ance 0.0223 0.0216 0.0140 0.0103 0.0188 0.0179 0.0146 0.0233 0.0144 0.0219 0.0240 0.0092 0.0144 0.0187 0.0173 0.0059 0.0177 0.0178 0.0215 0.0141 0.0105 0.0094 0.0120 0.0104 0.0136 0.0097 0.0133 0.0142 0.0124 0.0124 chance exceed- G 0.1129 0.1105 0.5% 0.1385 0.0296 0.0168 0.0642 0.0542 0.0323 0.1846 0.0313 0.1231 0.2412 0.0140 0.0314 0.0632 0.0491 0.0076 0.0525 0.0534 0.0300 0.0173 0.0154 0.0235 0.0181 0.0305 0.0162 0.0293 0.0336 0.0253 0.0253 ance chance exceed- W 1% 0.0111 0.0116 0.0113 0.0113 0.0112 0.0110 0.0116 0.0187 0.0178 0.0079 0.0151 0.0145 0.0196 0.0182 0.0203 0.0070 0.0152 0.0138 0.0044 0.0143 0.0142 0.0178 0.0081 0.0075 0.0094 0.0083 0.0077 0.0109 0.0100 0.0101 ance chance exceed- G 1% 0.0114 0.0117 0.0998 0.0789 0.0214 0.0120 0.0439 0.0391 0.0232 0.1312 0.0223 0.0869 0.1732 0.0101 0.0223 0.0451 0.0343 0.0055 0.0378 0.0368 0.0787 0.0216 0.0125 0.0162 0.0131 0.0218 0.0212 0.0242 0.0181 0.0183 ance chance exceed- W, weighted using equation; %, percent] W, W 2% 0.0116 0.0114 0.0112 0.0153 0.0142 0.0084 0.0058 0.0088 0.0160 0.0085 0.0147 0.0168 0.0052 0.0085 0.0120 0.0105 0.0032 0.0108 0.0143 0.0085 0.0060 0.0059 0.0070 0.0064 0.0088 0.0058 0.0086 0.0093 0.0078 0.0079 ance chance exceed- G 2% 0.1190 0.0690 0.0522 0.0149 0.0082 0.0281 0.0270 0.0159 0.0888 0.0151 0.0583 0.0070 0.0150 0.0306 0.0227 0.0038 0.0260 0.0239 0.0535 0.0150 0.0086 0.0082 0.0104 0.0091 0.0150 0.0081 0.0147 0.0167 0.0123 0.0127 ance chance exceed- W 4% 0.0111 0.0113 0.0120 0.0108 0.0062 0.0040 0.0082 0.0086 0.0064 0.0127 0.0061 0.0135 0.0036 0.0060 0.0089 0.0076 0.0022 0.0084 0.0077 0.0062 0.0042 0.0044 0.0048 0.0047 0.0067 0.0043 0.0067 0.0071 0.0057 0.0060 ance chance exceed- G Region 2 4% 0.0110 0.0457 0.0323 0.0100 0.0053 0.0167 0.0179 0.0104 0.0569 0.0097 0.0369 0.0780 0.0046 0.0096 0.0197 0.0141 0.0025 0.0172 0.0144 0.0344 0.0100 0.0056 0.0060 0.0063 0.0061 0.0101 0.0054 0.0099 0.0080 0.0085 ance chance exceed- W 0.0088 0.0072 0.0040 0.0023 0.0048 0.0057 0.0040 0.0092 0.0037 0.0078 0.0101 0.0022 0.0036 0.0058 0.0045 0.0013 0.0056 0.0044 0.0077 0.0040 0.0025 0.0029 0.0029 0.0030 0.0047 0.0027 0.0046 0.0047 0.0035 0.0039 10% ance chance exceed- G 0.0256 0.0157 0.0058 0.0028 0.0074 0.0101 0.0057 0.0296 0.0051 0.0187 0.0426 0.0026 0.0049 0.0104 0.0069 0.0014 0.0095 0.0067 0.0181 0.0057 0.0031 0.0035 0.0034 0.0036 0.0062 0.0031 0.0060 0.0061 0.0042 0.0049 10% ance chance exceed- W 20% ance 0.0072 0.0053 0.0031 0.0016 0.0031 0.0044 0.0029 0.0074 0.0026 0.0059 0.0085 0.0016 0.0024 0.0043 0.0031 0.0009 0.0042 0.0029 0.0059 0.0030 0.0018 0.0022 0.0027 0.0023 0.0040 0.0020 0.0037 0.0035 0.0024 0.0030 chance exceed- G 20% 0.0116 0.0116 0.0176 0.0094 0.0042 0.0018 0.0042 0.0070 0.0038 0.0188 0.0032 0.0285 0.0018 0.0031 0.0067 0.0041 0.0010 0.0065 0.0038 0.0040 0.0021 0.0025 0.0031 0.0026 0.0049 0.0022 0.0045 0.0042 0.0028 0.0034 ance chance exceed- W 0.0070 0.0044 0.0029 0.0012 0.0023 0.0040 0.0024 0.0069 0.0020 0.0051 0.0085 0.0013 0.0019 0.0036 0.0023 0.0007 0.0037 0.0022 0.0053 0.0026 0.0014 0.0019 0.0036 0.0020 0.0041 0.0017 0.0036 0.0029 0.0019 0.0026 50% ance chance exceed-
0.0140 0.0064 0.0036 0.0013 0.0027 0.0056 0.0029 0.0136 0.0024 0.0082 0.0219 0.0014 0.0022 0.0049 0.0028 0.0008 0.0051 0.0025 0.0085 0.0032 0.0016 0.0021 0.0043 0.0022 0.0049 0.0018 0.0042 0.0033 0.0020 0.0029 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 1 2 3 4 5 6 7 8 9
no. USGS station 02368326 02368329 02368500 02369000 02369500 02369800 02370000 02370200 02370500 02370700 02370750 02372500 02374500 02374970 02375000 02375500 02376000 02376033 02376079 02376300 02376500 02228500 02229000 02230000 02230500 02231000 02231230 02231250 02231253 02231268 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; Appendix 2 61 W 0.0112 0.0195 0.0178 0.0162 0.0168 0.0148 0.0179 0.0179 0.0219 0.0208 0.0134 0.0098 0.0149 0.0204 0.0165 0.0071 0.0074 0.0225 0.0208 0.0166 0.0173 0.0166 0.0191 0.0215 0.0153 0.0146 0.0170 0.0051 0.0204 0.0204 0.0100 0.2% ance chance exceed- G 0.0311 0.2% 0.0680 0.0512 0.0191 0.0396 0.0435 0.0324 0.0515 0.0515 0.1095 0.0872 0.0261 0.0153 0.0325 0.0799 0.0415 0.0096 0.0101 0.1260 0.0857 0.0419 0.0473 0.0425 0.0633 0.1005 0.0347 0.0447 0.0063 0.0804 0.0793 0.0157 ance chance exceed- W 0.5% ance 0.0116 0.0116 0.0119 0.0114 0.0160 0.0144 0.0084 0.0128 0.0134 0.0145 0.0145 0.0184 0.0173 0.0104 0.0073 0.0169 0.0132 0.0052 0.0054 0.0191 0.0172 0.0132 0.0139 0.0131 0.0164 0.0181 0.0136 0.0036 0.0168 0.0169 0.0074 chance exceed- G 0.0466 0.0352 0.0129 0.0267 0.0299 0.0220 0.0354 0.0354 0.0746 0.0588 0.0180 0.0103 0.0222 0.0543 0.0285 0.0066 0.0069 0.0865 0.0578 0.0245 0.0322 0.0283 0.0499 0.0690 0.0231 0.0212 0.0306 0.0043 0.0540 0.0543 0.0106 0.5% ance chance exceed- W 1% 0.0111 0.0119 0.0110 0.0119 0.0114 0.0134 0.0065 0.0102 0.0092 0.0125 0.0158 0.0145 0.0082 0.0055 0.0093 0.0142 0.0107 0.0039 0.0041 0.0164 0.0144 0.0106 0.0104 0.0141 0.0154 0.0093 0.0090 0.0027 0.0141 0.0142 0.0056 ance chance exceed- G 1% 0.0254 0.0091 0.0189 0.0216 0.0156 0.0256 0.0256 0.0534 0.0417 0.0130 0.0074 0.0159 0.0388 0.0206 0.0048 0.0050 0.0625 0.0408 0.0204 0.0231 0.0196 0.0384 0.0499 0.0159 0.0152 0.0220 0.0031 0.0380 0.0391 0.0074 0.0337 ance chance exceed- W W, weighted using equation] W, 2% 0.0117 0.0119 0.0117 0.0115 0.0118 0.0110 0.0096 0.0048 0.0080 0.0087 0.0071 0.0096 0.0096 0.0133 0.0120 0.0063 0.0040 0.0072 0.0085 0.0029 0.0030 0.0141 0.0084 0.0090 0.0079 0.0131 0.0069 0.0070 0.0088 0.0019 0.0040 ance chance exceed- G 2% 0.0110 0.0176 0.0062 0.0128 0.0150 0.0107 0.0178 0.0178 0.0365 0.0281 0.0090 0.0050 0.0264 0.0143 0.0033 0.0034 0.0433 0.0275 0.0140 0.0160 0.0127 0.0266 0.0347 0.0102 0.0105 0.0152 0.0021 0.0256 0.0270 0.0050 0.0233 ance chance exceed- W 4% 0.0119 0.0074 0.0034 0.0060 0.0067 0.0053 0.0075 0.0075 0.0109 0.0095 0.0046 0.0029 0.0054 0.0093 0.0065 0.0020 0.0021 0.0094 0.0064 0.0070 0.0056 0.0088 0.0108 0.0048 0.0052 0.0067 0.0013 0.0091 0.0095 0.0028 0.0088 ance chance exceed- G 4% 0.0117 0.0119 ance 0.0041 0.0084 0.0100 0.0071 0.0120 0.0238 0.0179 0.0060 0.0033 0.0074 0.0171 0.0096 0.0022 0.0023 0.0289 0.0174 0.0094 0.0107 0.0078 0.0155 0.0232 0.0062 0.0070 0.0100 0.0014 0.0167 0.0178 0.0033 0.0155 chance exceed- W 0.0050 0.0022 0.0041 0.0045 0.0036 0.0052 0.0051 0.0077 0.0062 0.0030 0.0018 0.0036 0.0062 0.0043 0.0012 0.0013 0.0090 0.0061 0.0044 0.0049 0.0036 0.0038 0.0080 0.0029 0.0035 0.0044 0.0008 0.0067 0.0066 0.0018 0.0060 10% ance chance exceed- G 0.0066 0.0025 0.0051 0.0058 0.0044 0.0071 0.0069 0.0128 0.0092 0.0035 0.0050 0.0045 0.0091 0.0055 0.0013 0.0014 0.0165 0.0089 0.0057 0.0065 0.0044 0.0047 0.0136 0.0034 0.0043 0.0056 0.0009 0.0101 0.0099 0.0020 0.0087 10% ance chance exceed- - W ex 20% ance ceed- 0.0047 0.0038 0.0019 0.0036 0.0035 0.0030 0.0041 0.0040 0.0059 0.0045 0.0022 0.0016 0.0030 0.0046 0.0033 0.0010 0.0010 0.0074 0.0043 0.0038 0.0041 0.0033 0.0019 0.0066 0.0034 0.0029 0.0032 0.0006 0.0060 0.0051 0.0016 chance G 20% 0.0011 0.0116 0.0046 0.0021 0.0043 0.0042 0.0036 0.0052 0.0049 0.0084 0.0058 0.0025 0.0017 0.0036 0.0059 0.0040 0.0010 0.0055 0.0046 0.0052 0.0040 0.0021 0.0098 0.0041 0.0034 0.0038 0.0007 0.0086 0.0068 0.0017 0.0060 ance chance exceed- W 0.0040 0.0033 0.0020 0.0039 0.0031 0.0032 0.0038 0.0035 0.0050 0.0035 0.0020 0.0016 0.0030 0.0037 0.0029 0.0009 0.0010 0.0068 0.0034 0.0039 0.0042 0.0043 0.0056 0.0062 0.0036 0.0029 0.0027 0.0006 0.0069 0.0044 0.0017 50% ance chance exceed-
0.0011 0.0049 0.0038 0.0022 0.0047 0.0036 0.0037 0.0046 0.0041 0.0063 0.0041 0.0022 0.0018 0.0035 0.0044 0.0033 0.0009 0.0095 0.0039 0.0047 0.0051 0.0052 0.0074 0.0084 0.0042 0.0034 0.0030 0.0006 0.0097 0.0054 0.0019 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 10 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 183 184 185
no. USGS station 02231280 02244320 02244420 02244473 02245050 02245140 02245255 02245260 02245400 02245470 02245500 02246000 02246150 02246200 02246300 02246460 02246497 02246522 02246600 02246828 02246832 02246900 02247000 02247200 02247480 02247510 02247600 02248000 02313400 02314200 02314500 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; 62 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.0119 0.0158 0.0159 0.0171 0.0220 0.0092 0.0123 0.0092 0.0189 0.0196 0.0156 0.0195 0.0122 0.0172 0.0202 0.0193 0.0121 0.0156 0.0170 0.0216 0.0166 0.0171 0.0260 0.0160 0.0224 0.0250 0.0091 0.0128 0.0179 0.0189 0.0132 0.2% ance chance exceed- G 0.2% 0.1117 ance 0.0211 0.0611 0.0374 0.0377 0.0454 0.0139 0.0224 0.0139 0.0609 0.0687 0.0361 0.0682 0.0220 0.0464 0.0764 0.0651 0.0216 0.0361 0.0452 0.1033 0.0424 0.0457 0.5152 0.0383 0.1223 0.2926 0.0136 0.0239 0.0516 0.0253 chance exceed- W 0.5% ance 0.0124 0.0126 0.0136 0.0185 0.0067 0.0094 0.0068 0.0153 0.0161 0.0123 0.0160 0.0093 0.0138 0.0166 0.0158 0.0092 0.0122 0.0135 0.0090 0.0182 0.0133 0.0137 0.0229 0.0126 0.0189 0.0218 0.0067 0.0098 0.0144 0.0154 0.0101 chance exceed- G 0.0253 0.0259 0.0308 0.0757 0.0093 0.0154 0.0095 0.0410 0.0467 0.0247 0.0467 0.0151 0.0319 0.0521 0.0447 0.0148 0.0245 0.0302 0.0142 0.0709 0.0291 0.0312 0.3508 0.0259 0.0840 0.2009 0.0093 0.0164 0.0352 0.0414 0.0172 0.5% ance chance exceed- W 1% 0.0111 0.0113 0.0112 0.0119 0.0100 0.0102 0.0158 0.0050 0.0074 0.0052 0.0126 0.0134 0.0099 0.0134 0.0073 0.0140 0.0132 0.0072 0.0098 0.0108 0.0069 0.0156 0.0108 0.0205 0.0101 0.0163 0.0194 0.0052 0.0077 0.0127 0.0079 ance chance exceed- G 0.0111 0.0211 0.0118 1% 0.0180 0.0187 0.0220 0.0538 0.0065 0.0068 0.0290 0.0335 0.0178 0.0337 0.0108 0.0230 0.0373 0.0323 0.0107 0.0175 0.0100 0.0512 0.0210 0.0225 0.2514 0.0184 0.0607 0.1452 0.0067 0.0253 0.0295 0.0123 ance chance exceed- W, weighted using equation] W, W 2% 0.0110 0.0110 0.0115 0.0077 0.0080 0.0088 0.0133 0.0036 0.0056 0.0038 0.0101 0.0078 0.0055 0.0091 0.0108 0.0055 0.0076 0.0084 0.0051 0.0132 0.0086 0.0089 0.0187 0.0078 0.0140 0.0174 0.0038 0.0059 0.0095 0.0102 0.0060 ance chance exceed- G 2% 0.0123 0.0130 0.0152 0.0365 0.0043 0.0077 0.0047 0.0197 0.0231 0.0123 0.0234 0.0075 0.0160 0.0255 0.0225 0.0074 0.0120 0.0140 0.0068 0.0355 0.0145 0.0156 0.1735 0.0125 0.0422 0.1008 0.0047 0.0082 0.0174 0.0200 0.0085 ance chance exceed- W 4% 0.0118 0.0058 0.0061 0.0068 0.0109 0.0024 0.0041 0.0027 0.0079 0.0088 0.0058 0.0089 0.0040 0.0070 0.0091 0.0086 0.0040 0.0058 0.0062 0.0036 0.0109 0.0065 0.0069 0.0173 0.0059 0.0156 0.0027 0.0043 0.0073 0.0078 0.0044 ance chance exceed- G 4% 0.1164 0.0114 ance 0.0081 0.0087 0.0101 0.0234 0.0028 0.0052 0.0032 0.0129 0.0155 0.0081 0.0158 0.0051 0.0107 0.0166 0.0151 0.0050 0.0080 0.0090 0.0044 0.0237 0.0096 0.0105 0.0083 0.0283 0.0672 0.0032 0.0055 0.0128 0.0057 chance exceed- W 0.0040 0.0040 0.0047 0.0075 0.0015 0.0027 0.0018 0.0056 0.0064 0.0037 0.0064 0.0026 0.0047 0.0061 0.0061 0.0025 0.0039 0.0042 0.0024 0.0080 0.0042 0.0048 0.0154 0.0040 0.0090 0.0130 0.0017 0.0028 0.0047 0.0050 0.0030 10% ance chance exceed- G 0.0050 0.0050 0.0062 0.0122 0.0016 0.0031 0.0019 0.0079 0.0094 0.0046 0.0095 0.0031 0.0062 0.0089 0.0088 0.0029 0.0049 0.0053 0.0027 0.0135 0.0054 0.0064 0.0710 0.0051 0.0166 0.0385 0.0019 0.0033 0.0062 0.0067 0.0035 10% ance chance exceed- - W ex 20% ance 0.0116 0.0034 0.0031 0.0040 0.0056 0.0013 0.0021 0.0014 0.0050 0.0055 0.0027 0.0054 0.0021 0.0037 0.0045 0.0049 0.0019 0.0033 0.0038 0.0020 0.0065 0.0030 0.0040 0.0149 0.0035 0.0076 0.0013 0.0022 0.0034 0.0035 0.0024 ceed- chance G 20% 0.0041 0.0036 0.0050 0.0078 0.0014 0.0024 0.0015 0.0066 0.0076 0.0031 0.0073 0.0024 0.0045 0.0059 0.0065 0.0021 0.0040 0.0047 0.0023 0.0095 0.0034 0.0050 0.0566 0.0042 0.0121 0.0272 0.0014 0.0025 0.0042 0.0043 0.0028 ance chance exceed- W 0.0115 0.0037 0.0027 0.0042 0.0046 0.0016 0.0020 0.0014 0.0055 0.0057 0.0022 0.0053 0.0021 0.0033 0.0037 0.0046 0.0017 0.0034 0.0045 0.0023 0.0059 0.0026 0.0039 0.0167 0.0038 0.0072 0.0012 0.0021 0.0028 0.0028 0.0025 50% ance chance exceed-
0.0043 0.0030 0.0051 0.0057 0.0017 0.0022 0.0015 0.0072 0.0075 0.0025 0.0068 0.0023 0.0038 0.0044 0.0056 0.0018 0.0040 0.0055 0.0025 0.0078 0.0029 0.0047 0.0560 0.0045 0.0104 0.0224 0.0012 0.0023 0.0032 0.0031 0.0028 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216
no. USGS station 02314600 02314700 02315000 02315200 02315500 02315550 02317500 02317600 02317620 02317630 02317748 02318000 02318500 02318600 02318700 02319000 02320700 02321000 02321500 02321600 02321700 02321800 02321975 02322000 02322016 02322049 02322500 02324000 02324400 02324500 02325000 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; Appendix 2 63 W 0.0128 0.0171 0.0244 0.0227 0.0152 0.0194 0.0190 0.0240 0.0225 0.0237 0.0248 0.0080 0.0180 0.0147 0.0044 0.0105 0.0046 0.0182 0.0076 0.0164 0.0164 0.0194 0.0207 0.0820 0.0050 0.0088 0.0200 0.0233 0.0176 0.0140 0.2% ance chance exceed- G 0.2% 0.0111 ance 0.0113 0.0239 0.0455 0.2207 0.1341 0.0341 0.0661 0.0619 0.1936 0.1276 0.1754 0.2618 0.0676 0.0370 0.0054 0.0171 0.0056 0.0718 0.0501 0.0498 0.0931 0.1358 0.0123 0.0062 0.0136 0.1099 0.5060 0.0628 0.0329 chance exceed- W 0.0211 0.0118 0.0118 0.0112 0.5% 0.0096 0.0137 0.0193 0.0158 0.0154 0.0207 0.0191 0.0203 0.0215 0.0059 0.0149 0.0032 0.0077 0.0033 0.0154 0.0056 0.0134 0.0134 0.0164 0.0180 0.0061 0.0036 0.0066 0.0171 0.0210 0.0147 ance chance exceed- G 0.0311 0.0117 0.0159 0.1515 0.0917 0.0230 0.0443 0.0417 0.1330 0.0876 0.1204 0.1768 0.0077 0.0452 0.0251 0.0037 0.0039 0.0492 0.0075 0.0338 0.0332 0.0622 0.0914 0.0084 0.0042 0.0093 0.0735 0.3447 0.0429 0.0225 0.5% ance chance exceed- W 1% 0.0112 0.0112 0.0110 0.0074 0.0186 0.0167 0.0094 0.0130 0.0127 0.0181 0.0165 0.0178 0.0190 0.0044 0.0126 0.0097 0.0024 0.0060 0.0024 0.0132 0.0043 0.0141 0.0158 0.0046 0.0026 0.0051 0.0149 0.1932 0.0125 0.0091 ance chance exceed- G 1% 0.0111 0.0224 0.1094 0.0660 0.0162 0.0310 0.0295 0.0961 0.0633 0.0870 0.1254 0.0056 0.0315 0.0180 0.0027 0.0084 0.0028 0.0355 0.0054 0.0239 0.0230 0.0435 0.0646 0.0060 0.0030 0.0067 0.0514 0.2472 0.0308 0.0162 ance chance exceed- W, weighted using equation] W, W 2% 0.0111 0.0119 ance 0.0054 0.0089 0.0164 0.0143 0.0072 0.0104 0.0102 0.0159 0.0142 0.0156 0.0168 0.0032 0.0103 0.0077 0.0017 0.0040 0.0018 0.0031 0.0090 0.0086 0.0138 0.0034 0.0019 0.0038 0.0127 0.0181 0.0104 0.0072 chance exceed- G 2% 0.0110 0.0113 0.0073 0.0155 0.0758 0.0454 0.0207 0.0198 0.0667 0.0440 0.0604 0.0846 0.0038 0.0209 0.0124 0.0018 0.0050 0.0019 0.0245 0.0037 0.0162 0.0150 0.0289 0.0437 0.0041 0.0021 0.0046 0.0342 0.1707 0.0212 ance chance exceed- W 4% 0.0119 0.0038 0.0069 0.0145 0.0121 0.0053 0.0080 0.0078 0.0139 0.0120 0.0135 0.0147 0.0023 0.0080 0.0059 0.0012 0.0032 0.0012 0.0090 0.0022 0.0070 0.0064 0.0097 0.0024 0.0013 0.0027 0.0105 0.0172 0.0082 0.0055 ance chance exceed- Region 3 G 4% 0.1146 0.0046 0.0104 0.0504 0.0298 0.0072 0.0134 0.0126 0.0445 0.0297 0.0403 0.0540 0.0026 0.0133 0.0083 0.0012 0.0038 0.0013 0.0162 0.0024 0.0107 0.0094 0.0185 0.0286 0.0027 0.0014 0.0031 0.0219 0.0139 0.0076 ance chance exceed- W 0.0111 0.0116 0.0115 0.0024 0.0048 0.0089 0.0036 0.0057 0.0048 0.0093 0.0106 0.0014 0.0058 0.0041 0.0007 0.0019 0.0008 0.0065 0.0014 0.0050 0.0044 0.0074 0.0098 0.0016 0.0008 0.0017 0.0082 0.0169 0.0057 0.0038 10% ance chance exceed- G 0.0110 0.0027 0.0063 0.0286 0.0164 0.0044 0.0080 0.0064 0.0256 0.0177 0.0232 0.0279 0.0016 0.0079 0.0051 0.0007 0.0021 0.0008 0.0091 0.0015 0.0065 0.0054 0.0174 0.0017 0.0008 0.0019 0.0131 0.0699 0.0076 0.0046 10% ance chance exceed- - W ex 20% ance 0.0011 ceed- 0.0022 0.0040 0.0101 0.0072 0.0031 0.0052 0.0034 0.0096 0.0080 0.0091 0.0094 0.0055 0.0035 0.0005 0.0014 0.0006 0.0051 0.0012 0.0045 0.0041 0.0071 0.0095 0.0013 0.0007 0.0014 0.0080 0.0180 0.0043 0.0031 chance G 0.0111 0.0114 20% 0.0024 0.0049 0.0200 0.0037 0.0070 0.0040 0.0181 0.0133 0.0164 0.0176 0.0012 0.0070 0.0041 0.0005 0.0014 0.0006 0.0062 0.0012 0.0055 0.0048 0.0096 0.0147 0.0014 0.0007 0.0015 0.0556 0.0051 0.0035 ance chance exceed- W 0.0011 0.0011 0.0026 0.0039 0.0097 0.0063 0.0035 0.0060 0.0025 0.0092 0.0079 0.0087 0.0082 0.0070 0.0037 0.0004 0.0006 0.0045 0.0012 0.0052 0.0054 0.0091 0.0120 0.0014 0.0007 0.0014 0.0104 0.0250 0.0036 0.0031 50% ance chance exceed-
0.0119 0.0011 0.0011 0.0114 0.0029 0.0047 0.0163 0.0086 0.0040 0.0080 0.0028 0.0150 0.0136 0.0126 0.0083 0.0041 0.0004 0.0006 0.0050 0.0012 0.0059 0.0061 0.0162 0.0014 0.0007 0.0014 0.0134 0.0547 0.0039 0.0033 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 217 218 219 220 221 222 223 224 225 226 227 228 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
no. USGS station 02326000 02326250 02326261 02326300 02326372 02326500 02326512 02326574 02326595 02326598 02326838 02326900 02234100 02234500 02235000 02235200 02236000 02236120 02236125 02236350 02236500 02236700 02237000 02239000 02240000 02240500 02240902 022409424 02240950 02240954 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; 64 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.0114 0.0117 0.0114 0.0113 0.0174 0.0236 0.0128 0.0126 0.0152 0.0128 0.0164 0.0101 0.0105 0.0076 0.0148 0.0142 0.0134 0.0145 0.0161 0.0108 0.0127 0.0185 0.0182 0.0129 0.0183 0.0109 0.0126 0.0132 0.0174 0.0200 0.0062 0.2% ance chance exceed- - G ex 0.2% ance 0.0110 0.1106 ceed- 0.0599 0.7057 0.0268 0.0262 0.0398 0.0215 0.0271 0.0225 0.0500 0.0172 0.0184 0.0379 0.0337 0.0294 0.0356 0.0474 0.0214 0.0212 0.0194 0.0266 0.0761 0.0713 0.0272 0.0728 0.0198 0.0259 0.0288 0.0599 0.0082 chance W 0.0118 0.0114 0.0116 0.5% 0.0145 0.0213 0.0100 0.0099 0.0122 0.0088 0.0101 0.0091 0.0134 0.0076 0.0079 0.0056 0.0106 0.0132 0.0087 0.0088 0.0083 0.0099 0.0155 0.0153 0.0101 0.0154 0.0084 0.0099 0.0105 0.0145 0.0172 0.0045 ance chance exceed- G 0.0411 0.0116 0.0511 0.0411 0.4697 0.0182 0.0179 0.0267 0.0144 0.0186 0.0154 0.0332 0.0123 0.0075 0.0252 0.0231 0.0202 0.0244 0.0326 0.0142 0.0145 0.0132 0.0177 0.0487 0.0186 0.0495 0.0136 0.0178 0.0198 0.0757 0.0056 0.5% ance chance exceed- W 1% 0.0111 0.0110 0.0123 0.0197 0.0080 0.0080 0.0102 0.0068 0.0082 0.0073 0.0059 0.0061 0.0043 0.0096 0.0093 0.0086 0.0096 0.0067 0.0070 0.0065 0.0077 0.0132 0.0131 0.0082 0.0132 0.0067 0.0080 0.0085 0.0123 0.0151 0.0034 ance chance exceed- G 1% 0.0111 0.0297 0.3249 0.0131 0.0128 0.0188 0.0101 0.0134 0.0230 0.0082 0.0087 0.0054 0.0176 0.0166 0.0146 0.0176 0.0236 0.0098 0.0105 0.0095 0.0122 0.0360 0.0349 0.0013 0.0355 0.0098 0.0129 0.0143 0.0297 0.0546 0.0041 ance chance exceed- W, weighted using equation] W, W 2% 0.0111 0.0110 0.0110 0.0102 0.0185 0.0062 0.0062 0.0078 0.0051 0.0064 0.0056 0.0086 0.0044 0.0045 0.0032 0.0074 0.0073 0.0068 0.0076 0.0090 0.0049 0.0054 0.0050 0.0057 0.0064 0.0051 0.0062 0.0067 0.0136 0.0132 0.0025 ance chance exceed- G 2% 0.2114 0.0117 0.0115 0.0207 0.0090 0.0088 0.0126 0.0067 0.0094 0.0077 0.0149 0.0056 0.0058 0.0038 0.0102 0.0122 0.0164 0.0064 0.0073 0.0066 0.0079 0.0243 0.0239 0.0092 0.0244 0.0068 0.0090 0.0099 0.0410 0.0379 0.0028 ance chance exceed- W 4% 0.0113 0.0082 0.0176 0.0046 0.0045 0.0058 0.0036 0.0048 0.0042 0.0063 0.0030 0.0032 0.0023 0.0054 0.0055 0.0051 0.0059 0.0071 0.0033 0.0039 0.0036 0.0039 0.0089 0.0088 0.0048 0.0091 0.0037 0.0046 0.0050 0.0082 0.0017 ance chance exceed- G 4% 0.0139 0.1307 0.0060 0.0058 0.0082 0.0044 0.0063 0.0052 0.0092 0.0036 0.0038 0.0026 0.0074 0.0076 0.0068 0.0082 0.0109 0.0040 0.0048 0.0044 0.0049 0.0159 0.0156 0.0062 0.0164 0.0046 0.0060 0.0067 0.0138 0.0256 0.0019 ance chance exceed- W 0.0011 0.0060 0.0172 0.0032 0.0028 0.0041 0.0023 0.0032 0.0027 0.0042 0.0017 0.0021 0.0014 0.0037 0.0036 0.0034 0.0040 0.0049 0.0021 0.0025 0.0024 0.0025 0.0067 0.0061 0.0032 0.0069 0.0023 0.0030 0.0034 0.0058 0.0091 10% ance chance exceed- G 0.0011 0.0083 0.0745 0.0037 0.0032 0.0050 0.0026 0.0037 0.0031 0.0052 0.0018 0.0023 0.0015 0.0044 0.0042 0.0040 0.0049 0.0063 0.0023 0.0028 0.0027 0.0028 0.0096 0.0085 0.0038 0.0100 0.0026 0.0035 0.0040 0.0079 0.0154 10% ance chance exceed- - W ex 20% ance 0.0011 0.0011 0.0050 0.0191 0.0027 0.0020 0.0037 0.0021 0.0025 0.0022 0.0040 0.0018 0.0034 0.0026 0.0026 0.0033 0.0038 0.0019 0.0018 0.0020 0.0023 0.0063 0.0046 0.0027 0.0062 0.0017 0.0024 0.0027 0.0046 0.0082 0.0008 ceed- chance G 20% 0.0011 0.0118 0.0062 0.0672 0.0030 0.0021 0.0042 0.0023 0.0028 0.0023 0.0047 0.0012 0.0020 0.0039 0.0029 0.0029 0.0038 0.0045 0.0020 0.0020 0.0021 0.0025 0.0082 0.0056 0.0030 0.0080 0.0018 0.0026 0.0030 0.0056 0.0008 ance chance exceed- W 0.0050 0.0302 0.0028 0.0016 0.0043 0.0025 0.0023 0.0020 0.0054 0.0008 0.0021 0.0010 0.0042 0.0022 0.0024 0.0032 0.0035 0.0025 0.0015 0.0020 0.0030 0.0076 0.0039 0.0027 0.0068 0.0015 0.0021 0.0026 0.0042 0.0089 0.0008 50% ance chance exceed-
0.0110 0.0056 0.0869 0.0030 0.0016 0.0048 0.0026 0.0024 0.0021 0.0062 0.0008 0.0022 0.0010 0.0046 0.0023 0.0025 0.0034 0.0038 0.0026 0.0016 0.0021 0.0033 0.0091 0.0043 0.0028 0.0080 0.0015 0.0022 0.0028 0.0046 0.0008 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 46 47 48 49 50 51 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 106 107 108 109 110 111 112 153 154 155
no. USGS station 02241900 02242451 02243000 02243500 02243530 02244000 02262900 02263800 02264000 02264051 02264100 02264495 02266200 02266300 02266480 02269000 02269520 02269720 02270500 02271500 02272000 02293694 02293986 02293987 02294068 02294650 02294898 02295013 02301900 02301990 02302260 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; Appendix 2 65 W 0.0116 0.0112 0.0121 0.0193 0.0172 0.0221 0.0183 0.0158 0.0151 0.0226 0.0188 0.0166 0.0208 0.0135 0.0162 0.0215 0.0168 0.0186 0.0134 0.0177 0.0106 0.0191 0.0162 0.0195 0.0141 0.0125 0.0088 0.0128 0.0195 0.0270 0.2% ance chance exceed- G 0.2% ance 0.0241 0.0220 0.0919 0.0578 0.2312 0.0733 0.0442 0.0392 0.3050 0.0817 0.0516 0.1412 0.0300 0.0479 0.1806 0.0534 0.0769 0.0297 0.0637 0.0186 0.0874 0.0481 0.0206 0.0958 0.0332 0.0255 0.0138 0.0215 0.0503 0.1768 chance exceed- W 0.5% ance 0.0112 0.0094 0.0090 0.0165 0.0142 0.0195 0.0154 0.0128 0.0121 0.0202 0.0160 0.0136 0.0182 0.0107 0.0133 0.0189 0.0139 0.0156 0.0105 0.0148 0.0081 0.0161 0.0132 0.0086 0.0166 0.0097 0.0066 0.0093 0.0150 0.0218 chance exceed- G 0.1189 0.0163 0.0151 0.0631 0.0393 0.1544 0.0496 0.0301 0.0263 0.2064 0.0559 0.0349 0.0968 0.0206 0.0328 0.1209 0.0366 0.0523 0.0198 0.0434 0.0127 0.0582 0.0323 0.0139 0.0642 0.0226 0.0172 0.0095 0.0144 0.0346 0.5% ance chance exceed- W 1% 0.0111 0.0114 0.0117 0.0075 0.0072 0.0144 0.0120 0.0175 0.0132 0.0106 0.0098 0.0183 0.0138 0.0161 0.0087 0.0168 0.0134 0.0083 0.0125 0.0063 0.0138 0.0109 0.0067 0.0143 0.0092 0.0077 0.0052 0.0070 0.0120 0.0181 ance chance exceed- G 1% 0.0116 0.0311 0.0109 0.0456 0.0280 0.1079 0.0354 0.0216 0.0185 0.1469 0.0402 0.0248 0.0699 0.0149 0.0236 0.0847 0.0265 0.0375 0.0137 0.0091 0.0400 0.0227 0.0098 0.0451 0.0163 0.0122 0.0068 0.0101 0.0250 0.0838 ance chance exceed- W, weighted using equation] W, W 2% 0.0110 0.0117 0.0114 0.0113 0.0057 0.0055 0.0124 0.0099 0.0158 0.0086 0.0077 0.0169 0.0092 0.0143 0.0069 0.0090 0.0149 0.0096 0.0062 0.0104 0.0048 0.0087 0.0050 0.0121 0.0072 0.0059 0.0038 0.0050 0.0094 0.0149 ance chance exceed- G 2% 0.0113 0.0079 0.0076 0.0316 0.0193 0.0715 0.0242 0.0149 0.0124 0.1004 0.0277 0.0170 0.0484 0.0104 0.0162 0.0565 0.0184 0.0258 0.0090 0.0215 0.0063 0.0257 0.0152 0.0067 0.0303 0.0083 0.0048 0.0067 0.0174 0.0566 ance chance exceed- W 0.0116 0.0041 0.0040 0.0103 0.0089 0.0140 0.0090 0.0067 0.0058 0.0156 0.0096 0.0072 0.0124 0.0052 0.0070 0.0130 0.0076 0.0093 0.0044 0.0084 0.0035 0.0088 0.0066 0.0036 0.0100 0.0055 0.0043 0.0028 0.0034 0.0069 4% ance chance exceed- - Region 4 G 4% ex ance 0.0211 0.0113 0.0117 ceed- 0.0051 0.0050 0.0129 0.0457 0.0162 0.0100 0.0081 0.0667 0.0182 0.0321 0.0070 0.0107 0.0364 0.0122 0.0173 0.0056 0.0144 0.0042 0.0154 0.0099 0.0044 0.0196 0.0076 0.0055 0.0032 0.0043 0.0370 chance W 0.0110 0.0024 0.0026 0.0078 0.0058 0.0123 0.0068 0.0048 0.0040 0.0144 0.0069 0.0053 0.0100 0.0034 0.0046 0.0053 0.0718 0.0028 0.0063 0.0023 0.0061 0.0047 0.0024 0.0078 0.0038 0.0029 0.0018 0.0022 0.0046 0.0086 10% ance chance exceed- G 0.0119 0.0027 0.0029 0.0121 0.0079 0.0272 0.0099 0.0061 0.0049 0.0408 0.0101 0.0069 0.0182 0.0041 0.0059 0.0219 0.0070 0.0106 0.0032 0.0088 0.0026 0.0084 0.0060 0.0027 0.0046 0.0033 0.0019 0.0026 0.0069 0.0225 10% ance chance exceed- W 20% 0.0111 ance 0.0016 0.0019 0.0064 0.0051 0.0126 0.0062 0.0041 0.0036 0.0148 0.0054 0.0047 0.0086 0.0027 0.0034 0.0042 0.0064 0.0026 0.0055 0.0019 0.0060 0.0043 0.0021 0.0074 0.0032 0.0025 0.0014 0.0019 0.0035 0.0072 chance exceed- G 20% 0.0017 0.0020 0.0085 0.0064 0.0238 0.0081 0.0049 0.0042 0.0336 0.0068 0.0057 0.0126 0.0030 0.0040 0.0190 0.0049 0.0084 0.0029 0.0070 0.0020 0.0077 0.0051 0.0022 0.0102 0.0036 0.0028 0.0014 0.0022 0.0050 0.0191 ance chance exceed- W 0.0012 0.0016 0.0061 0.0057 0.0176 0.0070 0.0044 0.0043 0.0199 0.0048 0.0052 0.0084 0.0024 0.0029 0.0149 0.0037 0.0071 0.0034 0.0060 0.0020 0.0087 0.0052 0.0023 0.0093 0.0032 0.0028 0.0013 0.0021 0.0030 0.0068 50% ance chance exceed-
0.0116 0.0012 0.0017 0.0070 0.0065 0.0284 0.0083 0.0048 0.0047 0.0350 0.0053 0.0059 0.0102 0.0026 0.0031 0.0220 0.0040 0.0084 0.0037 0.0069 0.0020 0.0107 0.0058 0.0024 0.0035 0.0030 0.0013 0.0026 0.0044 0.0212 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 11 12 13
no. USGS station 02302500 02303000 02303205 02303350 02303358 02303400 02303420 02303800 02306289 02307200 02309848 02309980 02310000 02310147 02310240 02310300 02310800 02310947 02311500 02312000 02312180 02312200 02312500 02312600 02312667 02312720 02313000 02231342 02231396 02231458 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; 66 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.0110 0.0241 0.0181 0.0138 0.0252 0.0170 0.0137 0.0229 0.0080 0.0176 0.0258 0.0137 0.0177 0.0102 0.0089 0.0244 0.0202 0.0198 0.0195 0.0237 0.0249 0.0123 0.0184 0.0280 0.0232 0.0258 0.0201 0.0148 0.0141 0.0236 0.0157 0.2% ance chance exceed- - G ex 0.2% ance 0.1190 0.0811 0.1136 ceed- 0.0993 0.0416 0.0244 0.0365 0.0240 0.0106 0.0395 0.1358 0.0241 0.0400 0.0151 0.0124 0.1041 0.0554 0.0526 0.0504 0.0167 0.0929 0.0200 0.0432 0.2304 0.0852 0.1354 0.0546 0.0277 0.0252 0.0912 0.0308 chance W 0.0111 0.0117 0.0192 0.0138 0.0103 0.0201 0.0129 0.0100 0.0179 0.0056 0.0132 0.0207 0.0100 0.0135 0.0074 0.0064 0.0194 0.0156 0.0152 0.0150 0.0080 0.0188 0.0198 0.0090 0.0139 0.0228 0.0183 0.0206 0.0156 0.0104 0.0187 0.5% ance chance exceed- G 0.0115 0.5% 0.0682 0.0286 0.0167 0.0814 0.0251 0.0160 0.0548 0.0071 0.0263 0.0930 0.0161 0.0274 0.0103 0.0085 0.0707 0.0374 0.0357 0.0342 0.0636 0.0771 0.0137 0.0292 0.0157 0.0581 0.0909 0.0375 0.0190 0.0171 0.0627 0.0209 ance chance exceed- W 1% 0.0119 0.0157 0.0109 0.0079 0.0165 0.0101 0.0074 0.0145 0.0040 0.0101 0.0171 0.0076 0.0106 0.0056 0.0048 0.0158 0.0124 0.0121 0.0061 0.0153 0.0162 0.0069 0.0109 0.0191 0.0148 0.0170 0.0124 0.0086 0.0080 0.0153 0.0090 ance chance exceed- G 1% 0.0110 0.0113 0.1126 0.0492 0.0206 0.0120 0.0586 0.0181 0.0389 0.0049 0.0181 0.0670 0.0197 0.0075 0.0061 0.0504 0.0266 0.0254 0.0244 0.0083 0.0459 0.0551 0.0099 0.0208 0.0416 0.0645 0.0271 0.0137 0.0122 0.0453 0.0149 ance chance exceed- W, weighted using equation] W, W 2% 0.0114 0.0118 0.0127 0.0084 0.0059 0.0135 0.0077 0.0052 0.0028 0.0082 0.0141 0.0055 0.0082 0.0041 0.0035 0.0127 0.0096 0.0093 0.0092 0.0045 0.0124 0.0132 0.0051 0.0083 0.0160 0.0138 0.0098 0.0065 0.0059 0.0123 0.0067 ance chance exceed- G 2% 0.0340 0.0142 0.0083 0.0404 0.0125 0.0070 0.0263 0.0032 0.0137 0.0462 0.0076 0.0137 0.0052 0.0042 0.0343 0.0182 0.0173 0.0168 0.0058 0.0319 0.0379 0.0069 0.0141 0.0771 0.0285 0.0435 0.0188 0.0096 0.0082 0.0315 0.0101 ance chance exceed- W 0.0097 0.0061 0.0042 0.0104 0.0056 0.0034 0.0084 0.0018 0.0050 0.0109 0.0038 0.0060 0.0029 0.0024 0.0096 0.0070 0.0067 0.0068 0.0032 0.0095 0.0102 0.0036 0.0060 0.0127 0.0089 0.0105 0.0072 0.0047 0.0040 0.0094 0.0047 4% ance chance exceed- - G 4% ex ance 0.0111 0.0112 0.0211 ceed- 0.0227 0.0094 0.0056 0.0266 0.0083 0.0042 0.0168 0.0020 0.0071 0.0305 0.0049 0.0092 0.0035 0.0028 0.0222 0.0121 0.0039 0.0215 0.0253 0.0046 0.0094 0.0503 0.0186 0.0278 0.0126 0.0064 0.0053 0.0065 chance W 0.0011 0.0067 0.0038 0.0027 0.0072 0.0035 0.0019 0.0054 0.0031 0.0076 0.0024 0.0040 0.0018 0.0015 0.0064 0.0048 0.0041 0.0046 0.0020 0.0067 0.0073 0.0023 0.0040 0.0092 0.0058 0.0070 0.0048 0.0030 0.0023 0.0065 0.0027 10% ance chance exceed- G 0.0117 0.0129 0.0053 0.0034 0.0147 0.0047 0.0022 0.0087 0.0012 0.0040 0.0170 0.0029 0.0056 0.0021 0.0017 0.0074 0.0059 0.0069 0.0023 0.0129 0.0155 0.0028 0.0057 0.0272 0.0100 0.0143 0.0073 0.0038 0.0028 0.0124 0.0034 10% ance chance exceed- - W ex 20% ance ceed- 0.0051 0.0028 0.0022 0.0054 0.0025 0.0017 0.0038 0.0010 0.0028 0.0058 0.0021 0.0031 0.0014 0.0012 0.0046 0.0040 0.0028 0.0038 0.0015 0.0053 0.0060 0.0018 0.0034 0.0070 0.0042 0.0051 0.0036 0.0023 0.0015 0.0051 0.0018 chance G 0.0011 0.0116 0.0090 0.0037 0.0027 0.0100 0.0032 0.0020 0.0055 0.0036 0.0025 0.0043 0.0016 0.0014 0.0076 0.0061 0.0038 0.0056 0.0018 0.0099 0.0125 0.0021 0.0048 0.0180 0.0066 0.0090 0.0053 0.0028 0.0018 0.0090 0.0022 20% ance chance exceed- W 0.0011 0.0042 0.0023 0.0020 0.0044 0.0021 0.0022 0.0028 0.0012 0.0033 0.0048 0.0023 0.0029 0.0012 0.0012 0.0036 0.0039 0.0022 0.0036 0.0014 0.0048 0.0056 0.0016 0.0033 0.0058 0.0033 0.0039 0.0031 0.0020 0.0044 0.0014 50% ance chance exceed-
0.0074 0.0029 0.0026 0.0078 0.0026 0.0029 0.0040 0.0013 0.0048 0.0092 0.0029 0.0040 0.0014 0.0013 0.0056 0.0064 0.0028 0.0056 0.0016 0.0091 0.0127 0.0019 0.0050 0.0136 0.0050 0.0065 0.0045 0.0025 0.0013 0.0078 0.0016 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 14 15 16 17 18 19 20 21 22 23 24 25 26 27 79 80 81 82 83 84 85 86 102 103 104 105 113 114 115 116 117
no. USGS station 02231565 02231600 02232000 02232155 02232200 02232400 02232450 02232500 02233001 02233102 02233200 02233475 02233500 02234000 02249007 02249500 02249518 02250000 02251000 02251500 02256000 02256500 02273000 02293000 02293050 02293400 02295420 02295630 02295637 02296260 02296500 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; Appendix 2 67 W 0.0144 0.0164 0.0154 0.0215 0.0253 0.0152 0.0236 0.0132 0.0131 0.0231 0.0264 0.0145 0.0282 0.0194 0.0266 0.0252 0.0267 0.0167 0.0196 0.0289 0.0197 0.0194 0.0180 0.0226 0.0265 0.0260 0.0162 0.0134 0.0156 0.0241 0.0187 0.2% ance chance exceed- G 0.2% ance 0.0263 0.0340 0.0297 0.0656 0.1224 0.0291 0.0904 0.0224 0.0223 0.0839 0.1539 0.0267 0.2447 0.0497 0.1605 0.1207 0.1646 0.0350 0.0506 0.3132 0.0516 0.0497 0.0414 0.0781 0.1562 0.1407 0.0329 0.0231 0.0305 0.0987 0.0452 chance exceed- W 0.0115 0.0114 0.0117 0.0106 0.0124 0.0167 0.0202 0.0186 0.0097 0.0097 0.0181 0.0213 0.0108 0.0230 0.0150 0.0214 0.0201 0.0215 0.0126 0.0151 0.0237 0.0152 0.0149 0.0137 0.0178 0.0213 0.0208 0.0122 0.0098 0.0191 0.0143 0.5% ance chance exceed- G 0.1108 0.5% 0.0177 0.0233 0.0202 0.0448 0.0837 0.0200 0.0620 0.0154 0.0152 0.0566 0.1055 0.0182 0.1674 0.0341 0.1095 0.0825 0.0240 0.0347 0.2138 0.0354 0.0336 0.0282 0.0536 0.1072 0.0954 0.0224 0.0156 0.0209 0.0673 0.0310 ance chance exceed- W 1% 0.0119 0.0117 0.0113 0.0081 0.0097 0.0089 0.0134 0.0167 0.0089 0.0153 0.0075 0.0074 0.0146 0.0177 0.0083 0.0193 0.0178 0.0166 0.0178 0.0099 0.0120 0.0200 0.0121 0.0108 0.0144 0.0178 0.0172 0.0095 0.0075 0.0091 0.0156 ance chance exceed- G 1% 0.0111 0.0111 0.0110 0.0126 0.0169 0.0145 0.0322 0.0604 0.0144 0.0460 0.0400 0.0761 0.0130 0.1206 0.0247 0.0787 0.0593 0.0784 0.0174 0.0251 0.1534 0.0256 0.0240 0.0202 0.0388 0.0774 0.0681 0.0161 0.0150 0.0482 0.0223 ance chance exceed- W, weighted using equation] W, W 2% 0.0116 0.0116 0.0060 0.0074 0.0067 0.0106 0.0137 0.0067 0.0122 0.0056 0.0084 0.0146 0.0062 0.0163 0.0093 0.0148 0.0135 0.0146 0.0075 0.0094 0.0170 0.0095 0.0091 0.0083 0.0147 0.0141 0.0071 0.0055 0.0069 0.0126 0.0088 ance chance exceed- G 2% 0.0117 0.0110 ance 0.0085 0.0100 0.0221 0.0419 0.0100 0.0310 0.0077 0.0145 0.0269 0.0529 0.0089 0.0837 0.0172 0.0544 0.0408 0.0527 0.0120 0.0175 0.1052 0.0178 0.0164 0.0140 0.0269 0.0536 0.0467 0.0076 0.0104 0.0330 0.0154 chance exceed- W 4% 0.0115 0.0116 0.0113 0.0115 0.0110 0.0041 0.0054 0.0047 0.0078 0.0106 0.0048 0.0093 0.0040 0.0039 0.0085 0.0043 0.0130 0.0069 0.0104 0.0054 0.0070 0.0136 0.0070 0.0066 0.0060 0.0087 0.0050 0.0039 0.0049 0.0095 0.0064 ance chance exceed- G 4% 0.0115 0.0118 0.0119 ance 0.0054 0.0079 0.0065 0.0145 0.0282 0.0067 0.0206 0.0052 0.0051 0.0171 0.0357 0.0058 0.0564 0.0366 0.0268 0.0334 0.0080 0.0688 0.0109 0.0094 0.0180 0.0357 0.0312 0.0072 0.0050 0.0068 0.0216 0.0102 chance exceed- W 0.0023 0.0035 0.0028 0.0050 0.0076 0.0031 0.0063 0.0024 0.0025 0.0054 0.0084 0.0026 0.0099 0.0046 0.0086 0.0071 0.0076 0.0034 0.0046 0.0101 0.0046 0.0045 0.0040 0.0059 0.0082 0.0080 0.0030 0.0025 0.0030 0.0063 0.0040 10% ance chance exceed- G 0.0116 0.0116 0.0028 0.0046 0.0035 0.0079 0.0170 0.0040 0.0030 0.0031 0.0087 0.0214 0.0031 0.0341 0.0068 0.0222 0.0147 0.0170 0.0045 0.0070 0.0374 0.0070 0.0067 0.0057 0.0103 0.0202 0.0191 0.0038 0.0031 0.0038 0.0057 10% ance chance exceed- W 20% ance 0.0015 0.0026 0.0019 0.0036 0.0062 0.0023 0.0048 0.0018 0.0020 0.0037 0.0068 0.0018 0.0080 0.0035 0.0070 0.0053 0.0055 0.0025 0.0036 0.0079 0.0035 0.0037 0.0032 0.0045 0.0064 0.0066 0.0021 0.0021 0.0021 0.0046 0.0029 chance exceed- G 0.0018 0.0034 0.0023 0.0053 0.0132 0.0029 0.0081 0.0021 0.0024 0.0054 0.0164 0.0021 0.0263 0.0050 0.0176 0.0099 0.0106 0.0031 0.0052 0.0249 0.0050 0.0055 0.0045 0.0073 0.0141 0.0155 0.0025 0.0025 0.0026 0.0077 0.0039 20% ance chance exceed- W 0.0011 0.0023 0.0015 0.0029 0.0055 0.0020 0.0039 0.0015 0.0018 0.0028 0.0060 0.0014 0.0071 0.0030 0.0063 0.0043 0.0025 0.0020 0.0031 0.0065 0.0030 0.0036 0.0031 0.0038 0.0053 0.0061 0.0016 0.0021 0.0017 0.0037 0.0023 50% ance chance exceed-
0.0115 0.0013 0.0029 0.0018 0.0041 0.0123 0.0025 0.0065 0.0018 0.0023 0.0039 0.0151 0.0016 0.0247 0.0043 0.0170 0.0076 0.0033 0.0025 0.0046 0.0190 0.0043 0.0057 0.0044 0.0061 0.0159 0.0019 0.0027 0.0020 0.0058 0.0030 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148
no. USGS station 02296750 02297088 02297100 02297155 02297251 02297310 02297320 02298123 02298202 02298608 02298760 02298830 02298928 02299120 02299160 02299410 02299800 02299950 02300000 02300018 02300032 02300034 023000355 02300037 02300038 02300039 02300100 02300200 02300500 02300530 02300700 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station; 68 Magnitude and Frequency of Floods for Rural Streams in Florida, 2006 W 0.0158 0.0158 0.0216 0.0205 0.2% ance chance exceed- G 0.2% ance 0.0313 0.0313 0.0671 0.0575 chance exceed- W 0.0119 0.0119 0.5% 0.0167 0.0157 ance chance exceed- G 0.5% ance 0.0215 0.0215 0.0448 0.0383 chance exceed- W 1% 0.0093 0.0093 0.0133 0.0124 ance chance exceed- G 1% 0.0156 0.0155 0.0313 0.0267 ance chance exceed- W, weighted using equation] W, W 2% 0.0070 0.0070 0.0103 0.0094 ance chance exceed- G 2% 0.0108 0.0108 0.0208 0.0177 ance chance exceed- W 4% 0.0051 0.0051 0.0074 0.0066 ance chance exceed- G 4% 0.0110 0.0072 0.0072 0.0133 ance chance exceed- W 0.0032 0.0032 0.0050 0.0038 10% ance chance exceed- - G ex 10% ance 0.0042 0.0042 0.0079 0.0053 ceed- chance W 20% ance 0.0024 0.0024 0.0043 0.0025 chance exceed- G 0.0030 0.0031 0.0069 0.0032 20% ance chance exceed- W 0.0021 0.0021 0.0045 0.0018 50% ance chance exceed-
0.0026 0.0027 0.0082 0.0022 G 50% ance chance exceed-
no. Variance of prediction values for gaging stations used in Florida regional regression analyses.—Continued Variance Map (pl. 1) 149 150 151 152
no. USGS station 02301000 02301300 02301350 02301500 Appendix 2. [USGS, U.S. Geological Survey; no., number; pl., plate; %, percent; G, computed from the Bulletin 17B analysis of gaging station;
Appendix 3 69 0.2 323,000 369,000 306,000 118,000 138,000 88,800 120,000 98,900 0.5 279,000 308,000 266,000 97,400 114,000 75,300 94,400 83,100 1 248,000 268,000 237,000 83,300 97,400 65,600 77,700 72,100 2 218,000 230,000 209,000 70,200 81,800 56,400 63,200 61,900 4 190,000 195,000 181,000 57,900 67,200 47,500 50,700 52,300 10 154,000 154,000 145,000 42,900 49,400 36,200 36,500 40,500 20 128,000 124,000 118,000 32,300 36,700 28,000 27,400 32,000 Peak flow, in cubic feet per second, for indicated exceedance probability percent Peak flow, 50 90,500 85,400 79,100 18,600 20,500 16,800 16,500 20,700
50 49 29 79 25 76 33 66 record (years) Period of 2.55 2.57 3.36 14.64 15.21 14.78 13.93 13.95 Storage (percent)
) 2 (mi area Drainage 6,970 7,280 7,880 9,390 9,640 17,200 17,600 19,200
name Station Chattahoochee, Fla. Blountstown, Fla. Sumatra, Fla. Ellaville, Fla. Luraville, Fla. Branford, Fla. Bell, Fla. Fla. Wilcox, Apalachicola River at Apalachicola River near Apalachicola River near Suwannee River at Suwannee River at Suwannee River at Suwannee River near Suwannee River near Flood-frequency estimates using PeakFQ version 5.2.
Station number , square miles] 2 02358000 02358700 02359170 02319500 02320000 02320500 02323000 02323500 Appendix 3. [mi Manuscript approved on February 25, 2011, by Sandy C. Cooper
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For additional information, please contact Richard Verdi, Hydrologist U.S. Geological Survey 2639 North Monroe St., Suite A-200 Tallahassee, Fla. 32303
[email protected] 850-553-3676 R.J. Verdi and J.F. Dixon—Magnitude and Frequency of Floods for Rural Streams in Florida, 2006—Scientific Investigations Report 2011–5034 Printed on recycled paper