Metropolitan utilities districts may, when deemed necessary by a resolution of the board of directors, temporarily lend the funds of one utility to the fund of another utility under its control, at the current market rate of interest as determined by the board of directors. In the case of emergency, or for the purpose of short-term financing of extensions, improvements, additions, and capital investments, the district may, by resolution of its board of directors, borrow money, for a term not to exceed five years, but the amount so borrowed shall not exceed ten percent of the depreciated plant value of the utility for which such money is borrowed.