One of the goals of the Program is to achieve target flows based on the current hydrologic condition of the Platte River. This hydrologic condition is calculated using a formula contained in the Program's Water Plan.
For more information, see these documents:
Report period
June 1-30, 2025
Dry
Target Flows
The final hydrologic condition designation for June 2025 is DRY based on a calculated index of 0.195 (DRY < 0.3). The calculated index was reduced from 0.198 to 0.195 with the inclusion of Monthly PDSI data for May and revised provisional flow data for May at the Grand Island gage.
Report period
May 1-31, 2025
Dry
Target Flows
Report period
March 1 - April 30, 2025
Dry
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) values for February 2025 reduced the calculated Hydrologic Conditions Index from 0.221 to 0.207 so the Final Hydrologic Condition remained "DRY" (HC Index < 0.25).
Report period
December 1, 2024 - February 28, 2025
Normal
Target Flows
Report period
October 1 - November 30, 2024
Dry
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) values for September 2024 increased the calculated Hydrologic Conditions Index from 0.174 to 0.202 but the Final Hydrologic Condition remained "DRY" (HC Index < 0.25).
Report period
August 1 - September 30, 2024
Dry
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) for July 2024 increased the calculated Hydrologic Conditions Index from 0.116 to 0.233 but the Final Hydrologic Condition remained "DRY" (HC Index < 0.29).
Report period
July 1-31, 2024
Normal
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) for June 2024 reduced the calculated Hydrologic Conditions Index from 0.460 to 0.310 but the Final Hydrologic Condition remained "NORMAL" (HC "DRY" only if HC Index < 0.31).
Report period
June 1-30, 2024
Normal
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) for May 2024 reduced the calculated Hydrologic Conditions Index from 0.574 to 0.561 but the Final Hydrologic Condition remained "NORMAL" (HC Index between 0.3 and 0.7).
Report period
May 1-31, 2024
Normal
Target Flows
Report period
March 1 - April 30, 2024
Normal
Target Flows
The Monthly Palmer Drought Severity Index (PDSI) for February 2024 reduced the calculated Hydrologic Conditions Index from 0.788 to 0.640 but the Final Hydrologic Condition remained "NORMAL" (HC Index > 0.25).
Report period
December 1, 2023 - February 29, 2024
Normal
Target Flows
Report period
October 1 - November 30, 2023
Normal
Target Flows
Report period
August 1 - September 30, 2023
Dry
Target Flows
Report period
July 1-31, 2023
Normal
Target Flows
Report period
June 1-30, 2023
Dry
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for May reduced the hydrologic condition index from 0.347 to 0.288 and changed the final hydrologic condition from "NORMAL" to "DRY"
Report period
May 1-31, 2023
Dry
Target Flows
Report period
March 1 - April 30, 2023
Dry
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for February reduced the hydrologic condition index from 0.433 to 0.118 and changed the final hydrologic condition from "NORMAL" to "DRY"
Report period
December 1, 2022 - February 28, 2023
Dry
Target Flows
Report period
October 1 - November 30, 2022
Dry
Target Flows
Report period
August 1 - September 30, 2022
Dry
Target Flows
Report period
July 1-31, 2022
Dry
Target Flows
Report period
June 1-30, 2022
Dry
Target Flows
Report period
May 1-31, 2022
Dry
Target Flows
Report period
March 1 - April 30, 2022
Dry
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for February reduced the hydrologic condition index from 0.432 to 0.118 and changed the final hydrologic condition from "NORMAL" to "DRY"
Report period
December 1, 2021 - February 28, 2022
Normal
Target Flows
Report period
October 1 - November 30, 2021
Normal
Target Flows
Report period
August 1 - September 30, 2021
Normal
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for July increased the hydrologic condition index from 0.216 to 0.355 and changed the final hydrologic condition from "DRY" to "NORMAL"
Report period
July 1-31, 2021
Dry
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for June reduced the hydrologic condition index from 0.433 to 0.295 and changed the final hydrologic condition from "NORMAL" to "DRY"
Report period
June 1-30, 2021
Normal
Target Flows
Report period
May 1-31, 2021
Dry
Target Flows
Report period
March 1 - April 30, 2021
Dry
Target Flows
The monthly Palmer Drought Severity Index (PDSI) values for February reduced the hydrologic condition index to 0.218 and changed the final hydrologic condition from "NORMAL" to "DRY"
Report period
December 1, 2020 - February 28, 2021
Normal
Target Flows
Report period
October 1 - November 30, 2020
Normal
Target Flows
Report period
August 1 - September 30, 2020
Normal
Target Flows
Report period
July 1-31, 2020
Normal
Target Flows
Report period
June 1-30, 2020
Wet
Target Flows
Report period
May 1 - June 1, 2020
Wet
Target Flows
Report period
March 1 - April 30, 2020
Normal
Target Flows
Report period
December 1, 2019 - February 29, 2020
Normal
Target Flows
Report period
October 1 - November 30, 2019
Wet
Target Flows
Report period
August 1 - September 30, 2019
Normal
Target Flows
Report period
July 1-31, 2019
Normal
Target Flows
Report period
June 1-30, 2019
Wet
Target Flows
Report period
May 1-31, 2019
Wet
Target Flows
Report period
March 1 - April 30, 2019
Normal
Target Flows
Report period
December 1, 2018 - February 28, 2019
Normal
Target Flows
Report period
October 1 - November 30, 2018
Normal
Target Flows
Report period
August 1 - September 30, 2018
Normal
Target Flows
Variables and Values
The mean July Palmer Drought Severity Index for two climate stations in Nebraska (NCDC Nebraska Divisions 5 and 8) was 1.32 equivalent to 45.3% of the 1947-1994 July conditions.
The July end-of-month content in Lake McConaughy as a percent of total capacity was 83.1%, equivalent to the 44.5% level of July end-of-month content over the 1947-1994 period.
For this period, the threshold index value is 0.29 for "normal" conditions. The current index value is greater than this and constitutes "NORMAL" conditions.
Note that for the August-September period, there are only "dry" and "normal" designations because "wet" targets are the same as "normal" targets for this period.
Report period
July 1-31, 2018
Normal
Target Flows
Report period
June 1-30, 2018
Normal
Target Flows
Variables and Values
To set the hydrologic condition for June, an index of conditions is computed using four Platte basin variables. These variables and their corresponding values were as follows:
For this period, the threshold index value is 0.30 for "normal" conditions and 0.70 for "wet" conditions. The current index value is greater than 0.30 and less than 0.70 and constitutes "???" conditions.
*based on temporary weekly PDSI data, to be updated when monthly PDSI data is available.
Report period
May 1-31, 2018
Normal
Target Flows
Variables and Values
The mean April streamflow in the Platte River at Grand Island was 2,055 cfs (provisional USGS data), or at the 62.9 percentile level of 1947-1994 April flows.
The April end-of-month content of Lake McConaughy was 1,467,900 acre-feet, equivalent to 84.2% of maximum capacity and 25.7 percentile level of the 1947-1994 April percent-of-capacity.
The April end-of-month content of three upper South Platte reservoirs (Antero, Eleven-Mile, and Cheesman) was 186,525 acre-feet, equivalent to the 68.7 percentile level of their 1947-1994 April contents.
The April 1 percent-of-normal snowpack in the North Platte Basin of Wyoming* (seven specific NRCS locations) was 101.4% of normal, equivalent to the 62.2 percentile level of 1947-1994 conditions.
The threshold index value is 0.30 for "normal" conditions and 0.70 for "wet" conditions. The current index value is greater than 0.30 and less than 0.70 and constitutes "NORMAL" condition.
Report period
March 1 - April 30, 2018
Normal
Target Flows
Variables and Values
The mean February streamflow for the Platte River near Grand Island gage (provisional USGS data) was 1,710* cubic feet per second, equivalent to the 51.3 percentile level of 1947-1994 February conditions. (*The USGS streamflow gage at Grand Island reported "ICE" conditions for the entirety of February. Data from the Overton gage was used as a surrogate)
The mean February Palmer Drought Severity Index for four climate zones in three states (NCDC divisions Colorado #4, Wyoming #8, and Nebraska #1 and #7) was -0.52, equivalent to the 45.6 percentile level of 1947-1994 February conditions.
The February end-of-month content of seven North Platte reservoirs (Alcova, Glendo, Gray Reef, Guernsey, Kortes, Pathfinder, and Seminoe) was approximately 2,125,352 acre-feet, equivalent to the 97.1 percentile level of 1947-1994 end-of-month February conditions.
For this period, the threshold index value is 0.25 for "normal" conditions. The current index value is less than this and constitutes "NORMAL" conditions.
Note that for the March-April period, there are only "dry" and "normal" designations because "wet" targets are the same as "normal" targets for this period.