A system comprising a desalination plant comprising a control system, wherein the control system is integrated with the desalination plant and configured to control the operation of one or more reverse osmosis arrays, one or more nanofiltration arrays, a blending system, or a combination thereof within the desalination plant, wherein the control system comprises: a control panel; a plurality of regulatory controllers (RCs); and a supervisory controller, wherein the SC is in signal communication with the CP, and with each of the plurality of RCs, wherein the SC is configured to: receive user inputs from the CP, and receive inputs from the plurality of RCs regarding data from a plurality of sensors (S1 to S14, Q1 to Q17) within the desalination plant, wherein each of the plurality of RCs is in signal communication with the plurality of sensors, wherein the plurality of RCs is configured to: receive data from one or more of the plurality of sensors, provide outputs to and receive permissions from the SC, and instruct one or more of a plurality of devices of the desalination plant in response to the received permissions from the SC, wherein the SC is configured to: monitor trends in the inputs regarding and/or predict outcomes from data received from the plurality of RCs and determine the permissions for each of the RCs based on the monitored trends, user inputs from the CP, or a combination thereof, and wherein the plurality of devices comprise a plurality of valves and pumps, wherein the plurality of valves and pumps include one or more valves configured to selectively combine at least a portion of a feed water from a feed water inlet line, at least a portion of a produced water in a PW blending line, or both with an RO permeate from an RO permeate feed line of the one or more RO arrays, an NF permeate from an NF permeate feed line of the one or more nanofiltration arrays, or both to produce an injection water having a composition within an operating envelope. a control panel; a plurality of regulatory controllers (RCs); and a supervisory controller, wherein the SC is in signal communication with the CP, and with each of the plurality of RCs, wherein the SC is configured to: receive user inputs from the CP, and receive inputs from the plurality of RCs regarding data from a plurality of sensors (S1 to S14, Q1 to Q17) within the desalination plant, wherein each of the plurality of RCs is in signal communication with the plurality of sensors, wherein the plurality of RCs is configured to: receive data from one or more of the plurality of sensors, provide outputs to and receive permissions from the SC, and instruct one or more of a plurality of devices of the desalination plant in response to the received permissions from the SC, wherein the SC is configured to: monitor trends in the inputs regarding and/or predict outcomes from data received from the plurality of RCs and determine the permissions for each of the RCs based on the monitored trends, user inputs from the CP, or a combination thereof, and wherein the plurality of devices comprise a plurality of valves and pumps, wherein the plurality of valves and pumps include one or more valves configured to selectively combine at least a portion of a feed water from a feed water inlet line, at least a portion of a produced water in a PW blending line, or both with an RO permeate from an RO permeate feed line of the one or more RO arrays, an NF permeate from an NF permeate feed line of the one or more nanofiltration arrays, or both to produce an injection water having a composition within an operating envelope.