Tracking River Health
Hydrologic conditions are updated regularly to show how current flows align with Program goals and species recovery needs.
Hydrologic Conditions
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:
December 1, 2025 - February 28, 2026
December 2025 - February 2026Target Flows
The final hydrologic condition designation for December 2025-February 2026 is NORMAL based on a calculated index of 0.296 (DRY < 0.25 < NORMAL).
December 1, 2025 - February 28, 2026
December 2025 - February 2026Target Flows
The final hydrologic condition designation for December 2025-February 2026 is NORMAL based on a calculated index of 0.296 (DRY < 0.25 < NORMAL).
October 1 - November 30, 2025
October-November 2025Target Flows
The final hydrologic condition designation for October-November 2025 is NORMAL based on a calculated index of 0.458 (0.25 < NORMAL < 0.67). The index value did not change with the inclusion of the Monthly PDSI data for September.
October 1 - November 30, 2025
October-November 2025Target Flows
The temporary hydrologic condition designation for October-November 2025 is NORMAL based on a calculated index of 0.458 (0.25 < NORMAL < 0.67).
August 1 - September 30, 2025
August-September 2025Target Flows
The final hydrologic condition designation for August-September 2025 is DRY based on a calculated index of 0.184 (DRY < 0.29). The index value increased from 0.176 to 0.184 with the inclusion of the Monthly PDSI data for July.
July 1-31, 2025
July 2025Target Flows
The final hydrologic condition designation for July 2025 is DRY based on a calculated index of 0.203 (DRY < 0.31). The index value increased from 0.199 to 0.203 with the inclusion of Monthly PDSI data for June.
June 1-30, 2025
June 2025Target 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.
May 1-31, 2025
May 2025Target Flows
March 1 - April 30, 2025
March-April 2025Target 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).
December 1, 2024 - February 28, 2025
December 2024-February 2025Target Flows
October 1 - November 30, 2024
October-November 2024Target 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).
August 1 - September 30, 2024
August-September 2024Target 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).
July 1-31, 2024
July 2024Target 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).
June 1-30, 2024
June 2024Target 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).
May 1-31, 2024
May 2024Target Flows
March 1 - April 30, 2024
March-April 2024Target 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).
December 1, 2023 - February 29, 2024
December 2023-February 2024Target Flows
October 1 - November 30, 2023
October-November 2023Target Flows
August 1 - September 30, 2023
August-September 2023Target Flows
July 1-31, 2023
July 2023Target Flows
June 1-30, 2023
June 2023Target 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"
May 1-31, 2023
May 2023Target Flows
March 1 - April 30, 2023
March-April 2023Target 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"
December 1, 2022 - February 28, 2023
December 2022-February 2023Target Flows
October 1 - November 30, 2022
October-November 2022Target Flows
August 1 - September 30, 2022
August-September 2022Target Flows
July 1-31, 2022
July 2022Target Flows
June 1-30, 2022
June 2022Target Flows
May 1-31, 2022
May 2022Target Flows
March 1 - April 30, 2022
March-April 2022Target 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"
December 1, 2021 - February 28, 2022
December 2021-February 2022Target Flows
October 1 - November 30, 2021
October-November 2021Target Flows
August 1 - September 30, 2021
August-September 2021Target 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"
July 1-31, 2021
July 2021Target 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"
June 1-30, 2021
June 2021Target Flows
May 1-31, 2021
May 2021Target Flows
March 1 - April 30, 2021
March-April 2021Target 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"
December 1, 2020 - February 28, 2021
December-January-February 2020-2021Target Flows
October 1 - November 30, 2020
October-November 2020Target Flows
August 1 - September 30, 2020
August-September 2020Target Flows
July 1-31, 2020
July 2020Target Flows
June 1-30, 2020
June 2020Target Flows
May 1 - June 1, 2020
May 2020Target Flows
March 1 - April 30, 2020
March-April 2020Target Flows
December 1, 2019 - February 29, 2020
December-January-February 2020Target Flows
October 1 - November 30, 2019
October-November 2019Target Flows
August 1 - September 30, 2019
August-September 2019Target Flows
July 1-31, 2019
July 2019Target Flows
June 1-30, 2019
June 2019Target Flows
May 1-31, 2019
May 2019Target Flows
March 1 - April 30, 2019
March-April 2018Target Flows
December 1, 2018 - February 28, 2019
December 2018 to February 2019Target Flows
October 1 - November 30, 2018
October and November 2018Target Flows
August 1 - September 30, 2018
August and September 2018Target 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.
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.
July 1-31, 2018
July 2018Target Flows
June 1-30, 2018
June 2018Target 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.
May 1-31, 2018
May 2018Target 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 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.
March 1 - April 30, 2018
March-April 2018Target 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)
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.
