![](media/image1.jpeg){width="1.7569444444444444in"
height="1.3159722222222223in"}**Deciding on Drought Triggers in the FERC
dam Relicensing Process**

Greg Carbone^\*^

Kirstin Dow^\*^, Hope Mizzell^\*\*^, Jinyoung Rhee^\*^, Dan
Tufford^\*\*\*^

*^\*^ Dept. of Geography, Univ. of South Carolina, Carolinas RISA*

*^\*\*^ SC State Climatology Office, SC DNR*

*^\*\*\*^ Dept. of Biological Sciences, Univ. of South Carolina,
Carolinas RISA*

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**Agencies and Interests in the FERC Relicensing Process:** Federal
Agencies**,** Licensee**,** State Agencies**,** Non-Agency Stakeholders

**Study Groups:** Water Quality, Hydropower, Water Supply, Fish and
Wildlife and Habitat Enhancement and Protection, Recreation, Shoreline
Management

**Low Inflow Protocol**

> Procedures for water use reductions during drought

-   ![](media/image4.png){width="4.4534722222222225in"
    height="1.4868055555555555in"} All Parties share responsibility to
    conserve water

-   Triggers for drought stages (D0 -- D4)

-   Reductions in hydropower generation commensurate with stage

-   Embrace state and local drought response laws

**Catawba-Wateree Project Summary of LIP Trigger Points (see table
above)**

^1^ Ratio of Remaining Useable Storage to Total Usable Storage

![](media/image5.png){width="2.5854166666666667in"
height="1.6791666666666667in"}^2^ 3-month numeric average of U.S.
Drought Monitor

^3^ Sum of rolling 6-month average streamflow as percentage of period of
record rolling average for same 6-month period

^4^ Stage 0 is triggered when any 2 of 3 trigger points are reached

**Regional Drought Mapping Tool**

Targets local-scale. Computes suite of monthly drought indices,
1950-2004. Based on empirical probability distributions of each index.
Allows creation of drought blends that address specific sensitivities.

> PDSI, PHDI, z-index
>
> ![](media/image6.png){width="3.2729166666666667in"
> height="1.9333333333333333in"}SPI (1,2,6,9,12,24-month)
>
> Precipitation (1,3,6,12,24,60-month)
>
> 7-day Streamflow
>
> 14-day Streamflow
>
> Streamflow (1,3,6,12,24-month)

**Scalable Vector Graphics (SVG)**

-   SVG defines vector-based graphics in XML (eXtensible Markup
    Language) format for the Web

**Dynamic Drought Index for Basins in NC and SC**

[**http://drought.dnr.sc.gov/**](http://drought.dnr.sc.gov/)

**User Input**

-   Display type

-   Input

    -   PDSI, PHDI, Z Index

    -   SPI in several time scales

    -   Precipitation and streamflow in several time scales

-   Raw data vs. percentile blend

**Map User Input**

-   Classification method

    -   Equal interval

    -   Quantile

    -   Natural break

    -   U.S. Drought Monitor-comparable category

        -   For any percentile blend

        -   For PDSI

        -   For SPI

        -   For weekly streamflow percentile

**Map Navigation Tools**

-   Full view

-   New map extent

-   Pan

-   New map center

-   Zoom in & out

-   Zoom slide

**Map Layers**

-   Visibility

-   Choropleth map

-   Boundary

-   Stations used

**Layer Aggregation**

-   Selected features of the same layer have been aggregated

-   Aggregation is based on the number of 4 km x 4 km grids with data
    used for spatial averaging of each feature

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height="2.2569444444444446in"}

**Thanks to:** *Lauren Gregory, Kirsten Lackstrom, and Ohnika Singh*