; (C) ensure that any funding provided through the MRRRI supplements, and not supplants, funding obtained through other agency budgets or other sources of funds for activities relating to the Mississippi River; and (D) strive to maintain, and where possible increase, the base level of funding for activities of the relevant Federal agency related to the Mississippi River, without regard to funding under the MRRRI. (h) Budget item (1) In general The Administrator shall, in the annual budget submission of the Agency to Congress, include a funding request for the MRRRI as a separate budget line item. (2) Inclusion The budget justification for the budget line item described in paragraph (1) shall include the amount to support the operation and activities of the Program Office. . 4. Mississippi River Corridor research centers and science plan (a) Definitions In this section: (1) Director The term Director means the Director of the United States Geological Survey. (2) FWPCA terms The terms MRRRI , MRRRI Director , Mississippi River Corridor , Mississippi River State , relevant Federal agency , Tribal government , and Tribal organization have the meanings given those terms in section 127(a) of the Federal Water Pollution Control Act. (b) Mississippi River Corridor Research Centers (1) In general The Secretary of the Interior shall coordinate with the MRRRI Director to establish a network of 4 Mississippi River Corridor Research Centers within the United States Geological Survey. (2) Location The network of research centers established under paragraph (1) shall consist of— (A) a National Mississippi River Corridor Research Center located at an office of the United States Geological Survey