c. Enclosed storm sewers, open drainage ditches, bridges, and culverts of a permanent design, adequate to carry off rainfall, shall be installed by the owner throughout the entire length of the drainage area within the subdivision in accordance with plans and specifications approved by the city engineer.
d. Drainage channels shall consist of natural banks and slopes where possible. Reinforced concrete pipe or concrete lining is permitted only where the city engineer or city council finds that this treatment is needed to maintain sufficient land area to accommodate development on an infill site that is designated in the comprehensive plan adopted by the City of Irving, as amended, or where a channel or grass lined channel cannot withstand the runoff velocities created from offsite drainage.
e. Fully developed watershed conditions shall be used for determining runoff for the conveyance storm and the flood mitigation storm.
(a) Right of entry; inspection and sampling. The director may enter the premises of any person discharging stormwater to the municipal separate storm sewer system (MS4) or to waters of the United States to determine whether the discharger is complying with all requirements of this article and with any state or federal discharge permit, limitation, or requirement. Dischargers shall allow the director ready access to all parts of the premises for the purposes of inspection, sampling, records examination, copying, and for performing any additional duties. Dischargers shall make available to the director, upon request, any SWPPPs, modifications to them, self-inspection reports, monitoring records, compliance evaluations, notices of intent, and any other records, reports, and other documents related to compliance with this article and with any state or federal discharge permit.
(1) Where a discharger has security measures in force which require proper identification and clearance before entry into its premises, the discharger shall make necessary arrangements with its security system so that, upon presentation of suitable identification, the director will be permitted to enter without delay for the purposes of performing his/her responsibilities.
(2) The director may set up on the discharger's property, or require installation of such devices as are necessary to conduct sampling and/or metering of the discharger's operations.
(3) The director may require any discharger to the MS4 or waters of the United States to conduct specified sampling, testing, analysis, and other monitoring of its stormwater discharges and may specify the frequency and parameters of any required monitoring.
(4) The director may require the discharger to install monitoring equipment as necessary at the discharger's expense. The discharger shall maintain the facility's sampling and monitoring equipment be at all times in a safe and proper operating condition at its own expense. The discharger shall calibrate all devices used to measure stormwater flow and quality to ensure their accuracy.
(5) Any temporary or permanent obstruction to safe and easy access to the facility to be inspected and/or sampled shall be promptly removed by the discharger at the written or verbal request of the director and shall not be replaced. The costs of clearing such access shall be borne by the discharger.
(6) Unreasonable delays in allowing the director access to the discharger's premises are a violation of this article.
(b) Search warrants. If the director has been refused access to any part of the premises from which stormwater is discharged and he/she is able to demonstrate probable cause to believe that there may be a violation of this article or any state or federal discharge permit, limitation, or requirement, or that there is a need to inspect and/or sample as part of a routine inspection and sampling program of the city designed to verify compliance with this article or any order issued under it, or to protect the overall public health, safety, and welfare of the community, the director may seek a search warrant from any court of competent jurisdiction.
City of Irving Stormwater Website
City of Irving Land Development Code
North Central Texas Council of Governments Stormwater Program