The matron or matrons of the county jail appointed under authority of section 30:8-10 of this title shall have care and control over all females committed to such county jail, subject to the authority of the sheriff of such county; and, subject to the authority of the sheriff, so far as practicable, she or they shall arrange for the segregation of the female inmates of such institution and, in general, have charge and control over all matters pertaining to the welfare, both physical and moral, of the female inmates of such institution. Such matron or matrons shall make an annual report to the board of chosen freeholders of such county respecting the general condition of the female inmates of such institution, each year, with recommendations concerning the necessary steps to be taken for the improvement of the welfare, both moral and physical, of such female inmates of such institution, as observed by her or them.