Definitions, Protocols, and Tools

Water Management Alternative (WMA)

Water Management Alternatives (WMAs) are combinations of construction and management practices selected and implemented by the landowner within a defined drainage basin of the ranch in order to produce the water retention or nutrient load reduction (TP and TN) services. WMAs on ranch parcels are intended to take advantage of existing water management infrastructure or make minor additions to infrastructure in order to generate cost-effective water management services.

Examples of construction practices that a rancher might consider individually or in combination on a WMA site are:

Culvert with riser structure
Culvert with riser structure.
  • Flashboard riser and/or weirs in existing uncontrolled ditches that drain by gravity from a site;
  • Constructing earthen berms or increasing the elevation of existing berms;
  • Constructing new above-ground impoundments or enhanced utilization of existing impoundments that require pumped inflows;
  • Rehydration of wetlands;
  • Collecting surface runoff from offsite areas that typically by-pass the site and diverting it to the connected onsite retention; and or
  • Site improvements that increase the potential for vertical infiltration from the site.

The selection of the practices and management actions that comprise the WMA as well as the number of acres the rancher includes in the WMA drainage basin vary as a result of the specific physical characteristics of the ranch, and the rancherís preferences that take into consideration the perception of risks and potential effects of enhanced water management on current land uses.

Environmental Service Definition

For the purposes of the NE-PES program there are two types of services provided by the rancher in the project WMAs- water retention or nutrient load reduction.

  • Water Retention WMAs retain on-ranch and/or regional stormwater to reduce the volume and rate of water flow to Lake Okeechobee during periods of high Lake levels as well as harmful estuary releases. As a consequence of retaining water, Water Retention WMAs also will retain nutrients that would otherwise leave the ranch in stormwater runoff.
  • Nutrient Removal WMAs divert off-site water onto the WMA and return water with reduced nutrients to the regional system. Nutrient Removal WMAs also will reduce the volume and slow the movement of water toward the Lake and estuaries under high lake level conditions.

Estimation of Environmental Service Provision

Ranchers proposing either a Water Retention or Nutrient Removal WMAs to the NE-PES Program must use one of two NE-PES approved methods to estimate the average annual change in water retention, or nutrient removal. These estimates will be included in the proposal submitted to the SFWMD and used to evaluate and rank proposals under the NE-PES program.

Potential Water Retention Model
Potential Water Retention Model

For Water Retention WMAs, the Potential Water Retention Model (PWRM) computes average annual water retention over a 10 year period of rainfall record that includes low and high rainfall days, weeks and months.

For Nutrient Removal WMAs, the Potential Phosphorous Removal Formula (PPRF) computes average annual geometric mean TP removal, recognizing the conditions that limit water diversion from the waters of the State to only excess conditions, the expected TP inflow concentrations in the water, the size of the proposed WMA and the current vegetative characteristics and management practices of the proposed WMA (existing wetlands or pasture). In WMAs with primarily pasture conditions (less than half of acreage is wetlands), a 30% TP load removal efficiency will be assumed.

In the estuary basins where nitrogen is the nutrient of concern, the PPRF, as developed for TP, will be utilized for service estimation until TN removal estimation tools are developed. The rancherís proposal will provide an estimate of the potential TP removal from using the PPRF, and the solicitation will require applicants to provide a conceptual plan for the WMA.

For all Nutrient Removal WMAs, data collected over a period of 3 years will be used to determine TP and TN removal efficiencies once the WMA is operational. These data may be used to modify the terms of the contract or the operation of the WMA during the life of the contract to optimize nutrient removal and better establish the level of service provided.

Request for Annual Payment

To receive the Annual Service Payment the rancher will compile the required documentation consisting of a Monthly Rancher Report filled out by the rancher and the Monthly Data Report provided by the Field Coordinator, the programís third party agent collecting the data. These two monthly reports include:

For Water Retention WMAs:

Monthly field team site visit
Monthly field team site visit
  • Daily surface water stage, pumping and rainfall records collected by the Field Coordinator from monitoring equipment installed at the WMA site.
  • Damages to the structures that compromise water retention capability, date of the damages or approved emergency operational changes and the basis for making any changes.
  • Documentation that board elevations at each WMA outlet were maintained as specified by the WMA design and operation plan.
  • Four quarterly water samples for TP and TN collected by the Field Coordinator.

For Nutrient Removal WMAs:

  • Pump records for daily volume of inflow, stage and nutrient (TP & TN) sampling by the Field Coordinator.

The rancher will submit both reports to the SFWMD on a monthly basis. Upon verification by the project manager of the SFWMD that all monthly reports are complete and contract compliance verified, the payment will be authorized. The annual payment will be made by the SFWMD within 30 days of the submission of the required documentation assuming all other contract requirements are met to the satisfaction of SFWMD.

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