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Horse Heaven SEPA


The State Environmental Policy Act (SEPA) is a Washington State law known as the Revised Code of Washington (RCW) 43.21C.  RCW 43.21C was enacted in 1971 which requires state and local agencies to identify and analyze the adverse environmental impacts of a proposal before making a decision on that proposal (RCW 43.21C.030). As part of analyzing the proposal for impacts, EFSEC sends data requests to the applicant requesting additional information or clarification regarding their proposal and/or the site. When a decision is made to prepare an Environmental Impact Statement (EIS) for SEPA review, the EIS process is initiated with a Determination of Significance (DS). EFSEC announces the DS in a Scoping Notice which begins a public comment period. EFSEC is required to consider all comments received during Scoping in determining the Scope of the EIS but is not required to respond to those comments in writing. A Scoping Report or Memo can be prepared and informs the public about the comments received during Scoping and how that information will set the Scope of the EIS. Once the Scope of the EIS is determined, a draft EIS is prepared.

For more information on the SEPA process visit the Certification Process page.

Draft Environmental Impact Statement (Draft EIS)

A Draft Environmental Impact Statement (EIS) provides information about the adverse environmental impacts of a project proposal. It examines a no action alternative which discusses impacts to the same environment but without the project proposal. It also presents reasonable alternatives, if identified, that could feasibly attain or approximate a proposal’s objectives, but at a lower environmental cost or decreased level of environmental degradation (WAC 197-11-440 (5)). SEPA considers both the natural environment (earth, air, water, plants, animals) and the built environment (e.g. land use, environmental health, cultural and historic resources, utilities) (WAC 197-11-660). The EIS focuses on the environmental resources that would have significant adverse environmental impacts. However, the EIS usually includes analysis of nonsignificant impacts because:

1) the determination of significance occurs after the analysis has occurred and all feasible mitigation has been identified;

2) the information reflects the thought process for determining an impact is nonsignificant;

3) nonsignificant impacts of the proposal considered together can increase an impact;

4) nonsignificant impacts of the proposal can contribute to a cumulative impact to a resource from multiple actions over time; and

5) identification of mitigation for nonsignificant impacts also incrementally benefits the environment.

The Draft EIS is reviewed by the public (including the applicant), other agencies, and tribal governments during a minimum 30-day comment period; the resulting input is used to improve the environmental analysis for the document and produce a Final EIS. The Draft EIS represents EFSEC’s best effort to provide complete and accurate information about the environmental impacts of the proposal, alternatives, and recommended mitigation to reduce those impacts. Public review of the Draft EIS provides an opportunity to identify missing, incomplete, or incorrect information to be addressed in support of the completeness and accuracy of the Final EIS.

The Final EIS is the official final document that analyzes the adverse environmental impacts of a proposal and must be used by agency decision makers, along with other relevant considerations or documents in making final decisions on a proposal. The lead agency considers comments on the proposal received during the Draft EIS comment period, responds to them, and includes those responses in the Final EIS. The Final EIS provides a basis upon which the responsible agency and officials can make the balancing judgment (e.g. environmental, welfare, social, economic) mandated by SEPA because it provides information on the environmental costs and impacts (WAC 197-11-448).

The Draft EIS was issued on December 19, 2022 and is open for public review and comment until the close of the Public Comment Period on February 1, 2023.

Where to get the Draft EIS

You may download or view the Draft EIS below or physical copies of the Draft EIS may be requested by contacting EFSEC at (360) 664-1345, P.O. Box 43172, Olympia, WA 98504-3172, or by e-mail at Printed copies will be provided for the cost of printing and electronic versions will be provided for the cost of the USB flash drive or CD. 

Copies of the Draft EIS along with the Horse Heaven Wind Farm Project Application for Site Certification, (EFSEC Application/Docket No. EF-210011) are also available for public review at the following locations:

Mid-Columbia Libraries

Kennewick Branch

1620 S Union Street

Kennewick, WA 99338

(509) 783-7878


Mid-Columbia Libraries

Prosser Branch

902 7th Street

Prosser, WA 99350

(509) 786-2533


Richland Public Library

955 Northgate Drive

Richland, WA 99352

(509) 942-7454

Mid-Columbia Libraries

Keewaydin Park Branch

405 S Dayton Street

Kennewick, WA 99336

(509) 586-3156


Mid-Columbia Libraries

West Pasco Branch

7525 Wrigley Drive

Pasco, WA 99301

(509) 546-8055


Washington State Library

Point Plaza East

6880 Capitol Boulevard SE

Tumwater, WA 98501

(360) 704-5200

Mid-Columbia Libraries

Pasco Branch

1320 W Hopkins Street

Pasco, WA 99301

(509) 545-1019


Mid-Columbia Libraries

West Richland Branch

3803 W Van Giesen Street

West Richland, WA 99353

(509) 967-3191 *(Sent 01/05/23)

Draft EIS Public Comment meeting February 1, 2023 5pm

A public comment meeting has been scheduled for the Horse Heaven Draft EIS

Video recordings of the February 1, 2023 Horse Heaven Draft EIS Public Comment Meeting (Part 1, Part 2, and Part 3

Comments Received 

The comment period has closed, thank you for your participation.

Comment period was held: December 19, 2022 - February 1, 2023. 

Comments - DEIS

Document Title Document Date
DEIS_0001-0100 02/13/2023
DEIS_0101-0200 02/13/2023
DEIS_0201-0300 02/13/2023
DEIS_0301-0400 02/13/2023
DEIS_0401-0500 02/13/2023
DEIS_0501-0600 02/13/2023
DEIS_0601-0700 02/13/2023
DEIS_0701-0800 02/13/2023
DEIS_0801-0900 02/13/2023
DEIS_0901-1000 02/13/2023
DEIS_1001-1100 02/13/2023
DEIS_1101-1200 02/13/2023
DEIS_1201-1300 02/13/2023
DEIS_1301-1400 02/13/2023
DEIS_1401-1500 02/13/2023
DEIS_1501-1600 02/13/2023
DEIS_1601-1700 02/13/2023
DEIS_1701-1800 02/13/2023
DEIS_1801-1900 02/13/2023
DEIS_1901-2000 02/13/2023
DEIS_2001-2100 02/13/2023
DEIS_2101-2200 02/13/2023
DEIS_2201-2300 02/13/2023
DEIS_2301-2400 02/13/2023
DEIS_2401-2430 02/13/2023
DEIS_2431-2497_Verbal Comments 02/13/2023

Video Recording of the Horse Heaven Draft EIS Overview Presentation

DEIS overview presentation

Data Requests

Data Request 4

Document Title Document Date
Data Request 4 Data Layers 11/02/2021
Data Request 4 Table 10/27/2021

Data Request 5

Data Request 6

Document Title Document Date
Data Request 6 Table 01/13/2022
Data Request 6 Response 02/07/2022

Data Request 7

Document Title Document Date
Data Request 7 Table 03/22/2023
Data Request 7 03/22/2023
Response to Data Request 7 04/21/2023

Data Request 8

Document Title Document Date
Data Request 8 Letter 05/08/2023
Data Request 8 Table 05/08/2023

Data Request 9

Document Title Document Date
Data Request 9 Letter 08/08/2023
Data Request 9 Memo 08/18/2023

SEPA Scoping

SEPA Comments Received

The SEPA Scoping comment period closed as of June 10, 2021.