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USGS Surface-Water Daily Statistics for Texas

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The statistics generated from this site are based on approved daily-mean data and may not match those published by the USGS in official publications. The user is responsible for assessment and use of statistics from this site. For more details on why the statistics may not match, click here.

USGS 08150700 Llano Rv nr Mason, TX


Mason County, Texas
Hydrologic Unit Code 12090204
Latitude  30°39'38", Longitude  99°06'32" NAD27
Drainage area 3,247  square miles
Contributing drainage area 3,242  square miles
Gage datum 1,225.36 feet above NGVD29
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00060, Discharge, cubic feet per second,
Day of
month
Mean of daily mean values for each day for water year of record in, ft3/s   (Calculation Period 1967-10-01 -> 2022-09-30)

Calculation period restricted by USGS staff due to special conditions at/near site
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1 454 184 198 186 205 407 224 240 207 216 272 202
2 239 211 191 183 379 336 235 308 359 171 250 198
3 219 241 189 187 648 311 236 768 201 158 921 197
4 210 367 198 186 337 543 219 197 198 248 1,820 196
5 202 304 205 185 296 344 296 158 184 488 365 196
6 197 250 215 196 242 256 244 187 169 309 386 196
7 194 220 262 215 211 287 180 184 162 240 287 195
8 190 209 222 218 242 240 156 163 1,490 799 267 197
9 191 202 216 207 293 294 150 137 508 641 251 198
10 189 196 207 219 346 259 146 136 194 432 237 195
11 186 196 225 217 747 261 193 138 171 221 224 195
12 185 194 240 195 357 403 731 424 170 272 214 193
13 184 192 238 188 248 272 182 324 177 1,930 210 192
14 183 189 216 182 291 249 151 283 162 1,260 206 192
15 183 187 204 377 288 215 142 212 162 355 585 194
16 184 207 227 741 347 265 229 177 175 2,920 713 192
17 184 192 207 394 254 624 224 328 300 575 1,170 188
18 184 195 202 361 286 384 171 264 694 300 381 186
19 182 194 199 327 239 222 159 175 261 509 287 187
20 181 185 248 249 230 192 155 153 209 559 257 224
21 179 188 276 282 309 178 143 158 257 311 242 293
22 178 190 255 236 282 199 153 146 505 246 232 254
23 176 212 218 236 217 172 145 165 300 293 229 231
24 175 221 202 210 323 177 176 368 205 900 222 215
25 174 302 195 196 529 190 195 251 197 377 223 205
26 182 232 202 184 673 167 285 213 221 271 225 207
27 189 208 352 218 398 234 179 182 326 276 221 205
28 188 200 272 240 311 202 164 298 220 246 214 197
29 212 228 223 214 353 211 146 853 191 333 208 194
30 196   209 197 345 326 137 849 333 388 204 193
31 189   196   301   199 399   297   1,300