TECHNICAL STANDARD MW-1 • Version 2.0 (Expanded Draft)

1. Purpose, Scope, and Use of This Standard

This Standard establishes uniform definitions, minimum design-basis parameters, minimum in-service condition standards, and objective declassification criteria for constructed stormwater Best Management Practices (BMPs). Version 2.0 expands the v1.0 framework in three directions: detailed component-level definitions for each practice family; step-by-step assessment instructions suitable for training and field execution; and formal integration of the Standard into the four MidAmerica Watershed.Org professional certifications, so that every credentialed practitioner is examined against the same definitions, floors, and procedures published here.

The animating problem is unchanged. Design manuals govern approval; inspection checklists govern noted deficiencies; nothing in common regional use governs the floor — the point at which an asset carried on an inventory as a rain garden, bioretention cell, or permeable pavement has degraded or was so minimally constructed that the classification is no longer true. Field reconnaissance across the St. Louis region has documented assets recorded as bioretention that are unplanted turf depressions of trivial dimension; permeable pavements sealed with sediment and oil with no restorative maintenance; and large publicly funded installations on which designed vegetation and surface treatments have been wholly lost. Where inventories, MS4 annual reports, and grant closeouts continue to carry such assets as functioning practices, program performance is misstated. This Standard supplies the vocabulary, the thresholds, and the due process to correct that.

The Standard is written to be adopted by reference in MS4 program documents, maintenance agreements, grant instruments, and municipal codes, and to be applied by certified assessors. Nothing here supersedes an authority having jurisdiction; where a jurisdictional design manual states a stricter parameter, the stricter parameter governs.

2. Definitions of Terms

Terms used in this Standard have the meanings below. These definitions are normative: certification examinations, assessment reports, and declassification determinations use these meanings.

3. Classification Framework

3.1 The two questions

Every assessment answers two independent questions. Type validity: does the asset, as built and as it exists, possess the defining elements of its recorded type? Functional condition: at what tier is it performing relative to design intent? A true bioretention cell can be Failed; a turf depression recorded as a rain garden is invalid as a matter of type regardless of how green it is. The remedies differ — condition failures are maintenance and enforcement matters; type failures are inventory-integrity and, where public funds were disbursed against the classification, fiscal-accountability matters.

3.2 Condition tiers

3.3 The residual-component rule

Residual subsurface or structural components — underdrains, aggregate reservoirs, pea gravel layers, curb openings, observation wells — do not preserve classification once the defining surface function of the type is lost. Buried pipe conveying water beneath a sealed or turf-converted surface is drainage, not treatment. Residual components shall be documented because they reduce restoration cost, but the asset is classified by what it functionally is, not by what was once installed.

4. Practice Families: Detailed Definitions, Standards, and Assessment Instructions

Each chapter provides: the expanded definition and functional narrative; component anatomy with failure indicators; design-basis and verification parameters; the condition floor; tier descriptors specific to the family; step-by-step Stage 1 (desktop) and Stage 2 (field) assessment instructions; common failure modes; and declassification guidance. The four families most represented among regional green-infrastructure inventories and most susceptible to misclassification — rain gardens, bioretention, bioswales, and permeable pavement — are treated at full depth. The remaining families are treated at working depth and will be brought to full depth in the next revision cycle.

4.1 Rain Garden

Definition. A shallow, vegetated surface depression receiving runoff from a small contributing area — typically a single rooftop, driveway, or lot — planted with species tolerant of periodic inundation, relying on amended native soil rather than engineered media, with or without an underdrain. The rain garden is the smallest and most numerous treatment practice, and the most frequently misapplied label: any mowed low spot can be called one. Under this Standard, an asset below the 50 square foot surface-area floor, or lacking a designed vegetation community, shall not be classified or credited as a rain garden.

How it works. Runoff enters via a defined inflow (downspout extension, curb cut, or graded swale), ponds to a shallow depth behind the overflow invert, and infiltrates through amended soil within 48 hours, with root systems maintaining porosity and providing uptake. Pollutant removal depends on soil contact and vegetation; hydrologic benefit depends on real ponding volume. A depression too small or too shallow to pond the design volume performs no measurable function regardless of appearance.

4.1.1 Component anatomy and failure indicators

4.1.2 Design-basis and verification parameters

4.1.3 Condition floor and tier descriptors

Condition floor (Tier 1/2 boundary). Not less than 75 percent designed vegetative cover; mowed turf not exceeding 25 percent of the footprint; sediment accumulation not exceeding 1 inch over more than 25 percent of the surface; inflow and overflow unobstructed; drawdown within 48 hours; trash removed at each maintenance cycle.

4.1.4 Assessment instructions

Stage 1 — Desktop screening. (1) Open the site in street-level imagery at the recorded coordinates; use the historical imagery series to view the earliest and most recent passes. (2) Confirm a depression or designed bed is visible at all; if the location shows continuous mowed turf with no bed edge, flag Type Matches = No (provisional). (3) Estimate footprint against reference objects (a mid-size sedan is roughly 80 sq ft); below-floor size is a provisional 4.1(d) finding. (4) Score vegetation: designed planting, partial turf invasion, or full turf. (5) Note inflow visibility (downspout, curb cut) and any sediment tongue, trash, or standing water. (6) Record imagery dates for every observation; assign provisional tier and priority.

Stage 2 — Field verification. (1) Photograph the practice from all four cardinal directions and the inflow/overflow close-up, with a scale object. (2) Tape the footprint and measure ponding depth from overflow invert to bed at three points. (3) Auger or probe to confirm amendment (friable, dark, non-compacted) versus native clay at the surface. (4) If recent rain or by ring test, verify drawdown ≤ 48 hr. (5) Estimate designed-community cover by quadrat at three representative locations. (6) Complete the field data sheet; retain all measurements in the evidence file.

4.1.5 Common failure modes

4.1.6 Declassification guidance

Declassify when: the designed vegetation community has been absent or replaced over more than 75 percent of the footprint beyond a growing-season cure; ponding volume is lost (no depression ≥ 2 in); the surface area is below the 50 sq ft floor; or the inflow has been permanently disconnected. Residual pea gravel, underdrain, or edging does not preserve the classification. Where the asset never met the definition as constructed, apply 4.1(d): retroactive correction and fiscal review if publicly funded.

4.2 Bioretention Basin / Cell

Definition. An engineered depression treating runoff through a designed media profile — mulch surface, sand-based bioretention media, choking/pea-gravel layer, and underdrained or infiltrating storage — planted with a designed vegetation community and fitted with defined inlets, a ponding zone, and an overflow. Bioretention is distinguished from a rain garden by its engineered media and from a detention basin by its treatment function: the media profile is the practice. An asset without a verifiable media profile is not bioretention whatever the record says.

How it works. Runoff enters through curb openings or piped inlets, ponds 6–12 inches over the media, and filters vertically through the profile at not less than the design rate; filtered water infiltrates or exits via underdrain. Pollutant removal occurs by filtration, sorption to media fines and organics, and biological uptake. Function collapses from the top down: a crusted, sealed, or buried media surface stops the practice cold even when every subsurface component remains intact — which is precisely why the residual-component rule exists.

4.2.1 Component anatomy and failure indicators

4.2.2 Design-basis and verification parameters

4.2.3 Condition floor and tier descriptors

Condition floor (Tier 1/2 boundary). Not less than 75 percent designed vegetative cover; mulch present where specified at 2–3 inches; sediment not exceeding 1 inch on the media surface; no standing water beyond 48 hours after rainfall; inlets, forebays, and outlets clear; erosion repaired; media surface not compacted, crusted, or sealed.

4.2.4 Assessment instructions

Stage 1 — Desktop screening. (1) Locate the cell in street-level and aerial imagery; use historical passes to bracket the trajectory (planted → thinning → turf is the classic arc). (2) Look for the engineered signatures visible from the street: curb openings, forebay rock, riser/overflow structure, mulch bed geometry. Absence of any engineered signature at the recorded coordinates is a provisional Type Matches = No. (3) Score vegetation state and mulch visibility. (4) Note standing water in imagery taken in dry conditions — a strong sealing indicator. (5) Note sediment tongues, trash accumulation, and mowing pattern crossing the bed. (6) Record imagery dates; assign provisional tier; queue Tier 3/4 candidates for Stage 2.

Stage 2 — Field verification. (1) Photograph all sides, each inlet, forebay, overflow, and any cleanout/observation well, with scale. (2) Confirm media by auger: engineered media is sandy, uniform, and dark-amended; native clay or imported topsoil at the surface indicates substitution — record the profile. (3) Measure ponding depth available below overflow. (4) Run a single-ring infiltration test at two locations or verify drawdown after wetting. (5) Open cleanouts; note dry-weather flow (short-circuit) or root intrusion. (6) Probe forebay sediment depth. (7) Complete data sheet; retain profile photos — they are the decisive evidence in type-validity disputes.

4.2.5 Common failure modes

4.2.6 Declassification guidance

Declassify when: in-service infiltration is below 0.1 in/hr or ponding persists beyond 96 hours (media failure) past cure; the designed vegetation community is lost over more than 75 percent of the cell past a growing-season cure; the media has been excavated, buried, regraded, or replaced with topsoil or turf; or contributing flow permanently bypasses the cell. The underdrain rule is absolute: subsurface conveyance without surface treatment function is a drain. Where media was never installed to specification, apply 4.1(d) with fiscal review where public funds were disbursed.

4.3 Bioswale / Vegetated Swale

Definition. A linear, gently sloped vegetated channel designed to convey runoff at low velocity while filtering it through vegetation maintained at treatment height and, where designed, infiltrating through amended soil or media. The bioswale is distinguished from a drainage ditch by three things it must have: a designed cross-section, designed vegetation providing filtration depth, and treatment intent documented in the approving plan. A mowed roadside ditch is not a bioswale merely because it is green.

How it works. Runoff enters along the length or at defined points, travels at shallow depth through vegetation whose stems provide hydraulic roughness and filtration, and either infiltrates through the amended bottom or discharges at reduced velocity and load. Function depends on contact: velocity low enough, vegetation tall and dense enough, and flow shallow enough that water moves through plants rather than over them. Scalped mowing and gully formation each destroy that contact in different ways.

4.3.1 Component anatomy and failure indicators

4.3.2 Design-basis and verification parameters

4.3.3 Condition floor and tier descriptors

Condition floor (Tier 1/2 boundary). Not less than 90 percent vegetated cover on bottom and side slopes; no continuous erosion gully or sediment bar occupying more than 25 percent of bottom width; check dams intact; mowing not scalping below 4 inches in the treatment reach.

4.3.4 Assessment instructions

Stage 1 — Desktop screening. (1) Trace the full length in aerial imagery; measure length and note the recorded coordinates position on the alignment. (2) In street-level passes, score vegetation state and mowing height where visible. (3) Look for gully shadows, sediment bars, rip-rap substitution, or a concrete flowline. (4) Historical series: check whether checks and planting visible at construction remain. (5) Flag piped or filled segments (surface continuity broken). (6) Assign provisional tier; note the specific stationing of deficiencies for Stage 2.

Stage 2 — Field verification. (1) Walk the full length; photograph representative reaches and every deficiency with stationing. (2) Measure bottom width, side slopes, and vegetation height at three stations. (3) Map gullies/bars as percent of bottom width; inspect each check dam for flanking. (4) Probe bottom for compaction or sealed fines where infiltration is designed. (5) Verify inflow points stabilized. (6) Data sheet with station-referenced findings.

4.3.5 Common failure modes

4.3.6 Declassification guidance

Declassify when the channel bottom has been converted to bare, rock, or concrete flowline over the majority of its length; when designed vegetation is permanently lost or maintained as scalped turf providing no filtration depth beyond cure; or when the cross-section has been filled, piped, or regraded such that the designed geometry no longer exists. Reclassification to a conveyance asset class may be appropriate where hydraulic function remains.

4.4 Permeable Pavement (Pervious Concrete, Porous Asphalt, Permeable Interlocking Pavers)

Definition. A load-bearing pavement system whose surface course admits water at high rates into an open-graded aggregate reservoir, discharging by infiltration or underdrain. Surface infiltration capacity is the defining treatment mechanism; it is also the property that dies first and invisibly. A permeable surface that sheds water is conventional pavement for classification purposes, whatever aggregate lies beneath — and the practice family is unique in that its defining function can be measured in minutes with a ring and a stopwatch.

How it works. Rain falling on (and limited run-on reaching) the surface passes through surface voids or paver joints into the reservoir, where it is stored and released by exfiltration or underdrain. Clogging is progressive and surficial: fines and organics seal the top fraction of an inch. Routine restorative vacuuming removes them; without it the surface seals within a few seasons of loading, after which only reconstruction-level milling or joint replacement restores function. Oil staining matters twice — it marks clogged, non-infiltrating zones and it marks untreated discharge running off a surface certified as treatment.

4.4.1 Component anatomy and failure indicators

4.4.2 Design-basis and verification parameters

4.4.3 Condition floor and tier descriptors

Condition floor (Tier 1/2 boundary). In-service surface infiltration not less than 10 in/hr at any tested location and no visible ponding or run-off sheeting during moderate rainfall; joints and voids free of sealed sediment crust; not more than 10 percent of area raveled, rutted, or patched impermeably; documented vacuum maintenance per the O&M schedule; oil staining addressed on identification.

4.4.4 Assessment instructions

Stage 1 — Desktop screening. (1) Locate the surface in aerial imagery; delineate the permeable area versus conventional. (2) In street-level imagery, look for the texture signature (open-graded surface or visible joint lines) and its absence where records claim it. (3) Score staining: individual drip spots versus lane-length streaks versus sheet discoloration — the progression maps to clogging extent. (4) Look for ponding stains, moss/weed lines in joints (fines proxy), seal-coat color, and conventional patches. (5) Wet-weather imagery, where the series includes it, showing sheet flow off the surface is high-value evidence. (6) Assign provisional tier; every Tier 3/4 candidate is a ring-test candidate.

Stage 2 — Field verification. (1) Photograph the surface pattern close-up (scale card) at clean and worst locations. (2) Run ASTM C1701/C1781 at a minimum of three locations: visually best, visually worst, and a wheel-path; record each rate. (3) Map percent of area stained, patched, or raveled. (4) Probe PICP joints for fines depth. (5) Locate and open any underdrain cleanout/observation port; note standing water. (6) Request or note absence of vacuum maintenance records — a documented 24-month gap with visible clogging is itself a Tier 4 trigger. (7) Data sheet with test locations mapped.

4.4.5 Common failure modes

4.4.6 Declassification guidance

Declassify when in-service infiltration is below 1 in/hr across the majority of the surface; when more than 25 percent has been overlaid, seal-coated, or impermeably patched; when the reservoir outlet is permanently blocked; or when no restorative maintenance has occurred within 24 months of documented clogging with staining or ponding. The reservoir does not save the classification: a sealed surface over open-graded stone is conventional pavement over expensive base.

4.5 Amended Soils / Impervious Area Disconnection

Definition and function. Compost amendment of compacted soils across a defined area, restoring infiltration and receiving disconnected rooftop or pavement runoff as dispersed sheet flow. The practice is invisible when healthy, which makes records (amendment depth, area, disconnection routing) and negative indicators (re-piping, compaction tracks, new coverage) the assessment currency.

4.5.1 Key components and parameters

Condition floor. Receiving area fully vegetated; no rill, channel, or compacted track; discharges remain dispersed and not re-connected to the storm system.

Assessment notes. Stage 1: verify in imagery that downspouts/discharges still daylight to the amended area and that no structure, pavement, or bare track has replaced it. Stage 2: probe for friable amended profile versus compaction; trace each discharge; infiltration test only where declassification is contemplated.

Declassification. Declassify when the area is re-compacted, paved, or built over; when discharge is re-piped or channelized to the sewer; or when field-verified infiltration is below 0.25 in/hr. Re-connection voids the practice regardless of soil condition.

4.6 Sand and Media Filters; Proprietary Treatment Units

Definition and function. Practices filtering runoff through a constructed sand or engineered media bed (surface, underground, perimeter, organic, or pocket configurations) or through a manufactured treatment device, with pretreatment and a positive outlet. Largely subsurface: access and records are defining maintenance conditions, and an unenterable, undocumented vault cannot be carried as functioning.

4.6.1 Key components and parameters

Condition floor. Bed free of sealing layer over 0.5 inch; pretreatment below 50 percent capacity; no water-quality-event bypass; inspection and maintenance records current.

Assessment notes. Stage 1 is limited: confirm access structures exist and are not paved over; surface filters can be scored visually. Stage 2: open access, measure sediment and water levels, verify drawdown, and reconcile maintenance records — the record gap is often the finding.

Declassification. Declassify when the bed is permanently saturated or sealed (drawdown beyond 96 hours); when pretreatment is full and consolidated; when the unit is abandoned, buried, or inaccessible; or, for proprietary units, when no maintenance service has occurred within twice the manufacturer interval.

4.7 Infiltration Trench / Infiltration Basin

Definition and function. Storage of runoff in an open-graded aggregate trench or earthen basin for exfiltration into native soils; defined by measurable drawdown into ground. Chronic standing water is the family's cardinal symptom: a basin that permanently holds water is functioning as an unengineered pond, not an infiltration practice.

4.7.1 Key components and parameters

Condition floor. Drawdown within the design standard; basin floor vegetation (where designed) healthy and not converted to a sediment flat; observation well accessible; no untreated upstream sediment source.

Assessment notes. Stage 1: standing water in dry-weather imagery, cattail/wetland signatures, and surface capping are the desktop tells. Stage 2: drawdown observation after wetting, sediment probing, and well inspection.

Declassification. Declassify when standing water persists beyond twice the design drawdown (sealed soils); when the trench surface is capped, paved, or landscaped over; or when the floor is sealed below 0.1 in/hr. Reclassify to a pond/detention class where hydraulic function genuinely remains and is wanted.

4.8 Detention Basins (Surface and Underground)

Definition and function. Temporary storage and controlled release of runoff for peak-rate control; dry or wet surface basins, or subsurface pipe/chamber/vault systems. The most numerous asset class in regional inventories and the most tolerant: turf is acceptable, and declassification is volumetric and structural, not vegetative.

4.8.1 Key components and parameters

Condition floor. Sediment not exceeding 20 percent of design storage; outlet unobstructed and unmodified; embankment free of woody growth on engineered fill, burrows, and seepage; underground systems on a documented inspection cycle.

Assessment notes. Stage 1: sediment deltas, outlet condition, embankment tree lines, and basin filling are all aerial-visible. Stage 2: sediment probing against as-built grades, outlet dimension check, embankment walkover; underground systems require confined-space-qualified entry or camera.

Declassification. Declassify when design storage is reduced by more than 50 percent; when the outlet is collapsed, buried, or modified such that design release no longer occurs; on embankment breach or regrading; or when an underground system is inaccessible or structurally compromised.

4.9 Runoff Reduction Devices (Rain Barrels, Cisterns, Harvesting) and Green Roofs

Definition and function. Distributed source controls: sealed storage vessels with managed drawdown, and vegetated roof assemblies over drainage and waterproofing layers. Numerous, small, and frequently abandoned in place — inventory credit for device classes shall rest on periodic sample verification, not on the presumption of continued existence.

4.9.1 Key components and parameters

Condition floor. Devices connected, sound, and operable with no permanent downspout bypass; green roofs at not less than 80 percent cover with drains clear.

Assessment notes. Stage 1: barrels and downspout routing are often street-visible; roofs need aerial or access. Stage 2 for device classes is a statistical sample with door-level verification; report class-level compliance rates.

Declassification. Declassify a device removed, disconnected, permanently bypassed, or inoperable beyond cure — a barrel that exists but is disconnected is not a BMP. Declassify a green roof on vegetation loss over 50 percent beyond a full growing-season cure or on media/drainage removal.

5. Assessment Protocol

5.1 Two-stage discipline

Stage 1 rapid visual screening — desktop imagery review or windshield survey — assigns a provisional tier and priority to every asset in scope and establishes probable cause for records requests and field work. Stage 2 field verification converts provisional findings into determinations. No asset shall be declassified, and no Tier 3 finding shall be published as final, on Stage 1 evidence alone. This discipline protects the assessor as much as the owner: a documented two-stage record is what distinguishes a defensible audit from advocacy.

5.2 Stage 1 standard procedure

For each asset: (1) open the recorded coordinates in street-level and aerial imagery; (2) review the historical imagery series and record the date of every pass relied upon; (3) apply the family-specific screening steps in the Section 4 chapters; (4) answer the two questions — provisional type validity and provisional tier; (5) record the three failure-mode flags (trash/debris; turf conversion or overgrowth; staining/sealing/clogging); (6) assign priority (High: provisional Tier 3–4 or type-invalid, publicly funded, or large; Medium: Tier 2; Low: Tier 1); and (7) where the asset is not visible from any imagery, mark Not Visible rather than guessing — NV assets route to field visit or records-only review. Every Stage 1 entry records the assessor, date, imagery dates, and the specific indicators observed.

5.3 Stage 2 standard procedure

Stage 2 is performed by a qualified assessor (Section 5.5) with landowner permission or from public vantage where permission is not granted, and comprises: dimensional confirmation against the family parameters; drawdown observation or surface infiltration testing where the family so specifies (single-ring for soil-based practices; ASTM C1701/C1781 for permeable pavements); media or soil-profile confirmation by auger or test pit where type validity is disputed; component-by-component photographic documentation with scale; and completion of the family data sheet. Findings are recorded against the defining elements and condition floor verbatim, so every conclusion traces to a stated requirement.

5.4 Evidence file and documentation standards

Each Tier 2 or worse determination is supported by an evidence file containing: asset identifier, recorded type, and location; all Stage 1 records with imagery dates; Stage 2 data sheets, photographs (dated, scaled, direction-noted), and test results; the responsible-party notice and proof of delivery; re-assessment records at the end of the cure period; and the determination memorandum citing the specific Standard provisions triggered. Photographs follow a fixed protocol: four cardinal views, each defining element close-up, and each deficiency with a scale object. Files are retained for not less than seven years.

5.5 Assessor qualifications

Stage 1 screening may be performed by any trained person working under a qualified assessor's review. Stage 2 assessments and all declassification determinations require a qualified assessor: a holder of the MidAmerica Watershed.Org Green Infrastructure Maintenance & Management certification or Master of Green Infrastructure credential, or an equivalent credential (CPESC, CMS4S, PE with stormwater practice) pending completion of the MW-1 examination module. Sampling design for population-level findings (Section 5.6) shall be reviewed by a Master-credentialed practitioner or equivalent.

5.6 Population-level findings

Where the purpose is programmatic (compliance rates, geographic equity analysis, reporting-integrity review), assets shall be surveyed either as a census of a defined subpopulation (for example, all publicly funded installations) or as a stratified random sample sized to support the stated confidence; strata should reflect practice family, ownership class, and geography. Published rates shall disclose the sampling frame, strata, sample sizes, and the NV (not visible) fraction. Equity findings — differential condition by geography or demography — shall be computed from the same rubric applied uniformly across all strata.

6. Declassification Criteria and Procedure

6.1 Universal triggers

Any asset shall be declassified when any of the following persists beyond the cure period: (a) the defining treatment surface has been removed, buried, paved, built over, or converted to another use; (b) contributing runoff has been permanently rerouted so the practice receives no design flow; (c) the asset cannot be located, accessed, or verified at its recorded coordinates; (d) the recorded classification never matched the constructed condition (misclassification at intake) — corrected retroactively for reporting purposes and referred for fiscal review where public funds were disbursed against the classification; or (e) maintenance obligations have been formally abandoned with no successor.

6.2 Family triggers

The family-specific triggers are stated in each Section 4 chapter (subsection .6 for full chapters). Where a family trigger and a universal trigger both apply, cite both.

6.3 Procedure

(1) Assessment: documented Stage 2 condition assessment identifying the trigger(s). (2) Notice: written notice to the responsible party stating the deficiency, the Standard provisions triggered, the required cure, and the cure period (12 months standard; 180 days where an executed maintenance agreement specifies corrective timelines; one full growing season where the deficiency is vegetative). (3) Re-assessment at the end of the cure period. (4) Determination: recorded with the evidence file; inventory, credit, and reporting corrected. (5) Pathway: a declassified asset may be restored and re-certified to its original type, or formally re-recorded as a type it actually satisfies (a failed bioretention cell retaining storage and controlled release may be re-recorded as detention under 4.8).

6.4 Reporting integrity

Once an asset is Tier 3 or Tier 4, continued representation of the asset as a functioning BMP in MS4 annual reports, permit compliance statistics, grant closeout documents, or public inventories is a misstatement of program performance. Adopting programs shall reconcile inventories annually, shall not carry declassified assets in credited totals, and shall disclose the count and disposition of Tier 3/4 assets in annual reporting. Where misclassification at intake involved public or ratepayer funds, the adopting program shall refer the matter for fiscal review.

6.5 Evidence file

The declassification evidence file follows Section 5.4 and additionally includes the notice and delivery record, any owner response, and the final determination memorandum signed by the qualified assessor and, for adopting programs, the program official.

7. Integration into MidAmerica Watershed.Org Certifications

This Standard is the normative reference for the classification, condition, and assessment content of all four MidAmerica Watershed.Org certifications. Curriculum modules, knowledge checks, and examinations shall use the Section 2 definitions verbatim, the Section 3 framework, the Section 4 family chapters, and the Section 5–6 procedures. The matrix below allocates MW-1 content across the certification track and states the competency each credential certifies against this Standard.

7.1 Curriculum allocation matrix

7.2 Learning objectives by credential

Cert 1 — GI Planning & Design. The credentialed planner/designer can state the defining elements and design-basis parameters of each family; designs practices that meet or exceed the classification floors (no sub-50-square-foot "rain gardens"; media profiles and pretreatment sized to the Standard); specifies O&M plans that name the restorative maintenance each family requires; and can explain to a client why a practice designed at the floor fails at the first maintenance lapse.

Cert 2 — GI Installation & Construction. The credentialed installer can verify at acceptance that what was built matches the definition — media depth and composition, surface infiltration by the applicable ASTM method, elevations and drawdown; produces the as-built record that later assessments depend on; and understands that intake misclassification (4.1(d)/6.1(d)) originates at construction and carries fiscal consequences on funded projects.

Cert 3 — GI Maintenance & Management. The credentialed maintainer/manager can execute Stage 1 and Stage 2 assessments per the Section 4 instructions; scores condition against the floors and tier descriptors; distinguishes restorative from cosmetic maintenance and schedules the former; assembles a compliant evidence file; and supports notice, cure, and re-assessment under Section 6.

Cert 4 — Master of Green Infrastructure. The Master practitioner holds determination authority: adjudicates type-validity disputes (including test-pit evidence); designs statistically defensible population studies under 5.6; renders declassification determinations and reclassification pathways; judges fiscal-referral thresholds; and represents findings to boards, regulators, and auditors.

7.3 Knowledge-check and examination requirements

Each curriculum module mapped in 7.1 concludes with a knowledge check drawn from this Standard; item banks shall cite the governing section for every item. Examination blueprints shall weight Section 4 (family standards) at not less than 40 percent for Certs 2 and 3. Practical examinations for Cert 3 include a scored Stage 1 screening exercise on imagery and a Stage 2 data-sheet completion; for Cert 4, a full determination package on a supplied evidence file. Certificate renewal requires re-examination on Standard revisions within one cycle of adoption.

7.4 Use of the Standard in training materials

Slide decks, module scripts, and field guides shall quote definitions, floors, and triggers verbatim with section citations, so the curriculum and the Standard cannot drift apart. The MW-1 Quick Reference card is the approved classroom and field summary. Where training materials paraphrase, the paraphrase is non-normative and the Standard governs.

8. Adoption, Maintenance, and Revision

Jurisdictions and programs may adopt this Standard by reference in MS4 program documents, maintenance agreements, grant instruments, and codes, and may phase application beginning with publicly funded and publicly credited assets where the accountability interest is greatest. MidAmerica Watershed.Org maintains the Standard on a public review cycle; comments are docketed and dispositioned in a published log; and certification item banks are updated within one cycle of each revision. Interpretation requests are answered in writing by Master-credentialed reviewers and compiled into published interpretation guidance.

9. References

Maryland Department of the Environment, Maryland Stormwater Design Manual, Volumes I and II (2000, as revised). USEPA, Stormwater Best Management Practice fact sheet series; MS4 Program Evaluation Guidance. ASTM C1701/C1701M, Infiltration Rate of In Place Pervious Concrete. ASTM C1781/C1781M, Surface Infiltration Rate of Permeable Unit Pavement Systems. Metropolitan St. Louis Sewer District, Rules and Regulations and Engineering Design Requirements, and MSD Project Clear BMP maintenance and inspection program documents (regional context). WEF/ASCE-EWRI, Design of Urban Stormwater Controls (MOP 23). Parameter values herein are proposed regional minimums subject to the public comment process; where an authority having jurisdiction states stricter values, the stricter values govern.