appropriation to carry out the following activities included in the Border Security Improvement Plan submitted under section 439: (A) Acquisition, construction, and installation of physical barriers, tactical infrastructure, cameras, sensors and other technology. (B) Acquisition, construction, renovation, and improvement of short-term detention facilities used for processing of individuals detained by U.S. Customs and Border Protection and long-term detention facilities used for individuals detained by U.S. Immigration and Customs Enforcement, including facilities to accommodate family units. (C) Acquisition, construction, renovation, and improvement of port of entry facilities. (2) Amounts in the fund shall remain available until expended. (d) Limitation on expenditure (1) Amounts deposited in the Fund may not be used for any activity except those provided for in this section. (2) The Secretary may not expend amounts from the Fund in any fiscal year in which the Border Security Improvement Plan has not been submitted pursuant to section 439. (e) Limitation on obligation The Secretary may not incur an obligation under a contract or other agreement entered into to carry out an activity under this section in excess of the unobligated balance, at the time the contract or agreement is entered into, of the Fund required to be used to satisfy the obligation. (f) Border security surcharge (1) In general Notwithstanding any other provision of law— (A) the Secretary shall charge a surcharge of— (i) $40 on the immigrant user fee established under section 286(m) of the Immigration and Nationality Act ( 8 U.S.C. 1356(m) )