TO MITIGATE the city’s flood problem, the Mandaue City Council has passed an ordinance requiring owners of houses, commercial and industrial establishments, and land developments to put up stormwater management facilities such as rainwater tanks, reservoirs and cisterns to harvest rainwater, or face fines and imprisonment.
The measure, dubbed “Stormwater Management Ordinance,” was passed on third and final reading last November.
The ordinance also mandates the creation of a water board to recommend water management policies.
City Councilor Jesus P. Arcilla, chairman of Planning and Development, said the initiative targets to control and minimize increases in rainwater run rates and volume and decrease the chances of soil erosion and stream channel erosion.
He explained that if establishments harvest rainwater and recycle it for use, such as for flushing toilets, watering plants and cleaning, there will be less water to overflow on streets and cause floods, and this will also help reduce the city’s scarcity of potable water supply at the same time.
“So before modagan ang tubig ulan sa gawas sa buildings, aduna na kitay istraktura nga mag harvest ini. Imagine ug mostly sa Mandaue adunay stormwater structure, ma lessen ang tubig nga mudagayday sa gawas,” Arcilla told SunStar Cebu on Sunday Dec. 10, 2023.
(So before the rainwater runs outside the buildings, we have a structure to harvest it. Imagine if most buildings in Mandaue had a stormwater structure, there would be less water flowing outside.)
The ordinance also mandates the creation of a water board.
Structure parameters
The law applies to all houses, buildings, subdivisions, land developments, and government offices and projects costing over P250,000, including those constructed before the ordinance’s approval. It gives a three-year leeway for the building of water conservation structures that comply with the provided standard.
The ordinance mandates establishing a rainwater tank with a 400-liter capacity for every 30-square-meter area for small houses and other residential buildings.
An additional 300 liters is required for every 20 square meters of increased roof area, while a tank with a 1,000-liter capacity is needed for houses with a 90-square-meter area.
Large residential buildings would need water tanks with 2.0 cubic meter capacity for a 100-square-meter area and add 1.0 cubic meter for every 50-square-meter increased roof area.
Lastly, commercial or industrial institutions and other structures would need a water tank with a one-cubic-meter water capacity for every 30-square-meter area and an additional 1.50 cubic meters for every 50- square-meter increase in roof area.
For the rainwater tank installed below ground, the design should be provided with proper access for inspection and a system to collect water for use. Cistern tanks bigger than five cubic meters capacity must contain a pump with a pipe system showing their utilization.
Each stormwater management structure (SMS) must at least include a detention basin with 20 cubic meters per 1,000 square net area (total gross land area) and addition of 10 cubic meters for every 500 square meters, retention basin or lagoon with 15 cubic meters per 1,000 square meters net area and addition of 7.5 cubic meters for every 500 square meters, swales or infiltration beds, which will cover 2.5 percent of the land area, and timely off-site drainage improvements such as storm inlets, sewers, culverts, channel modifications, land-filling and other drainage facilities.
Requires approval
“No final subdivision plan, subdivision construction plan, site plan, or building permit shall be approved by the City unless it can be demonstrated by the owner or developer of such property that the proposed development will not result in damage to any adjacent or downstream property,” the ordinance reads.
The design, size and construction plan of the SMS must be approved by the Office of the Building Official (OBO) before construction and will be required before payment of real property tax.
Real property tax is a levy on real properties, such as land, buildings, machinery and other improvements affixed or attached to real properties not specifically exempted under the law. It accrues on the first of January and is payable in one or four equal installments.
Also, OBO can withhold a structure’s building permit if its SMS master plan does not comply with the standard.
Ideal retention areas
The City will also require all developers to submit a Drainage Impact Assessment (DIA) report to determine critical rainfall, estimate peak flow under pre-development and post-development scenarios, simulate hydrodynamic modeling of urban flood to produce flood maps, depict flood depths and duration, and flood extent, among others.
Also, the ordinance identified seven areas ideal for developing regional retention or detention basins to address frequent flooding and its increasing magnitude.
These are barangays Canduman, Casuntingan, Tingub, Pagsabungan, Cubacub, Tawason and Jagobiao with an existing basin.
Water board
The law also mandates the creation of a Water Management Advisory Board comprising Mayor Jonas Cortes as the chairperson, and the following as members: the city administrator, executive secretary to the mayor, City Engineering, Legal, Planning and Development, and Environment and Natural Resources Offices, OBO and Sangguniang Panlungsod committees on environment and infrastructure.
The Department of Environment and Natural Resources, Department of Public Works and Highways, National Water Resources Board, Metropolitan Cebu Water District, and private stakeholders are also included as its members.
The board is tasked to recommend policies regarding water management, advise and coordinate with the local water district and other water suppliers to ensure Mandaue’s adequate water supply, form a technical working group, and meet every quarter or as needed to form additional measures.
Incentives and penalties
Arcilla said compliant building owners or administrators within a year will be given incentives in the form of a property tax rebate equivalent to five percent of the assessed value.
On the other hand, violators after the grace period will be subjected to 30 days to six months of imprisonment, a fine of P1,000 to P5,000, or both, depending on the court’s discretion.
From building owners who will not comply with the ordinance for five years, including the three-year grace period, an additional five percent surcharge on the assessed realty tax shall be collected.