Environmental Site Assessment Thailand: Field ESA

Service overview: environmental field services

Environmental site assessment (ESA) is the collection of real field data on groundwater level and quality, aquifer properties, flow direction and soil contamination, for EIA reports, operating permits and land purchase decisions. Laboratory analysis, EIA reports and remediation planning are done by licensed or accredited partners under one SPN quotation.

Scope

What it covers

Monitoring wells to ASTM D5092 · water level · data logger · decommissioning
Slug / pumping tests and resistivity surveys for aquifers
Test pits · hand auger · low-flow sampling and contamination maps
Baseline data and EIA monitoring programmes

When to use

When you need it

Factories and projects with EIA monitoring conditions
Operating permit applications
Risk checks before buying or selling land
Locating aquifers and groundwater flow direction

Deliverables

What you receive

Well completion logs and wellhead levels
Water level tables and graphs, piezometric maps and aquifer test results
Lab results from accredited partner laboratories
Engineer-signed field report, ready for the EIA consultant

Monitoring wells and groundwater level

SPN installs monitoring wells that stay usable for the life of the project and records groundwater levels systematically, by scheduled manual readings and by automatic logging.

Monitoring Well InstallationASTM D5092Drilling and installing PVC wells with a slotted screen in the target aquifer, washed-sand filter pack, bentonite seal against cross-layer contamination and a lockable well cap. Each well is developed before the first sampling and documented in a Well Completion Log.
Groundwater Level MeasurementScheduled readings with a water level meter (accuracy ±1 cm), with all wells referenced to the same top-of-casing levels. Results are given as tables and trend graphs by season or at the interval set in the EIA conditions.
Groundwater Level Data LoggerA pressure transducer in the well records water level automatically at a set interval, with barometric compensation. It captures the effect of rain, tides and pumping that manual readings miss.
Well DecommissioningASTM D5299Sealing disused monitoring wells or boreholes with bentonite or cement grout over the full depth, cutting the wellhead and restoring the ground. This stops an old well becoming a shortcut for contaminants into the aquifer; a decommissioning record is provided.

Hydrogeology and aquifers

SPN determines aquifer properties, depth, extent and groundwater flow direction for EIA reports, dewatering work and well positioning.

Slug Test / Pumping TestA slug test is quick to run in an existing monitoring well without pumping large volumes. A pumping test pumps continuously and reads surrounding observation wells; both give hydraulic conductivity (K) and transmissivity (T) for dewatering assessment and effects on neighbouring areas.
Resistivity Survey (VES / ERT)ASTM D6431Current is passed into the ground through surface electrode lines to produce a resistivity section. It is used to estimate aquifer depth and thickness, saline water zones or anomalies that may relate to contamination, before choosing confirmation boreholes.
Groundwater Flow Direction (Piezometric Map)Water levels from at least 3 wells on a common datum are used to draw a piezometric map showing flow direction and gradient. It identifies upgradient and downgradient wells for a contamination monitoring plan.
Soil Electrical / Thermal ResistivityWenner 4-pin and thermal resistivity testing for earthing systems, solar farms and underground power cables. These tests are described on SPN's field soil testing service page.

Soil and groundwater sampling and contamination

SPN collects samples and takes field measurements itself, then sends them under chain of custody to accredited partner laboratories.

Soil Sampling (Test Pit / Hand Auger)Samples from test pits (2–4 m deep) and hand auger holes (1–3 m deep) on a grid or at risk points such as chemical storage tanks and material stockpiles. Samples go into clean containers and are kept chilled in transit.
Low-flow Groundwater SamplingASTM D6771The well is pumped at a low rate until field readings stabilise, then sampled, which reduces sediment and loss of volatiles. pH, EC, DO, ORP and turbidity are measured on site and samples reach the laboratory within the required holding time.
Laboratory Analysis (accredited partner lab)Heavy metals (As, Cd, Cr, Pb, Hg) by ICP-MS, VOCs by GC-MS, TPH (GC-FID), general water quality and microbiology. Analysis is done by accredited partner laboratories; SPN delivers the samples and follows up the results.
Contamination Boundary MappingSampling locations, lab results and groundwater flow direction are combined on one map showing exceedances and the approximate extent. It is used to plan the next sampling round or to support risk assessment.
Risk Assessment and Remediation Plan (partner)Health and environmental risk assessment and remediation planning are done by specialist partners. SPN hands over all field data and can carry out field work during remediation.

EIA field data and monitoring programmes

SPN provides correct groundwater and soil data from before the project starts, so EIA consultants and agencies can use it directly.

Baseline Environmental SurveyWells are installed and groundwater level, groundwater quality and soil samples are collected before construction or operation. These values are the reference for later monitoring reports.
Environmental Monitoring ProgramWell locations, parameters and the measurement schedule are designed to match the measures in the EIA report, together with the project's environmental consultant, so every round is comparable.
Field Report and EIA Report SupportSPN issues an engineer-signed field report (well logs, water level tables, sampling records, lab results). The EIA report itself is prepared by a consultant licensed by ONEP (สผ.), with SPN supplying complete data.

Which work does SPN do itself, and which is done by partners?

SPN carries out all field work directly; laboratory analysis and EIA reporting are done by partners, with SPN coordinating.

Work	Carried out by	Note
Monitoring well installation	SPN directly	ASTM D5092
Soil and groundwater sampling	SPN directly	ASTM D6771 (low-flow groundwater)
Test pit / hand auger	SPN directly	1–4 m deep
Slug test / pumping test	SPN directly	K and T values
Resistivity survey (VES / ERT)	SPN directly	ASTM D6431
Well decommissioning	SPN directly	ASTM D5299
Laboratory chemical analysis	Accredited partner lab	Coordinated by SPN
EIA report	Partner consultant licensed by ONEP (สผ.)	Coordinated by SPN

Where has SPN done environmental field work?

Monitoring well · Samut Prakan

Monitoring well and 8 m standpipe piezometer in soft clay

SPN installed a groundwater monitoring well paired with an 8 m standpipe piezometer in soft clay in Samut Prakan. The instruments are read monthly for project monitoring and groundwater records.

8 m standpipe piezometer
Soft clay
Monthly readings

Full case study (Thai) →

Sampling and wells · field gallery

Test pits, hand auger sampling and monitoring well installation

SPN field crews have collected soil samples from test pits and by hand auger next to a building, and drilled and installed monitoring wells, including Monitoring Well No.3. Water samples from this work were analysed in the laboratory.

Test pit and hand auger soil sampling
Monitoring Well No.3 completed
Laboratory water analysis

Site photos from SPN projects

Test pit excavated for environmental soil sampling — Test pit soil sampling

Completed groundwater monitoring well No.3 with well cap — Monitoring Well No.3 completed

Hand auger soil sampling next to a building — Hand auger sampling next to a building

Groundwater samples being analysed in a laboratory — Water samples analysed in the laboratory

How does an environmental project with SPN work?

Send site information and objectiveSite plan or coordinates, the objective (EIA condition, land sale or purchase, or after a spill) and any required parameter list.
Plan wells, sampling points and parametersSPN sets well positions and depths, sampling points and the analysis list with the partner lab, with a free quotation within 24 hours.
Prepare the siteUnderground pipes and cables are checked before drilling, site access is arranged and sample containers are prepared for each parameter.
Field workWell drilling and installation, well development, water level readings, aquifer tests and soil and groundwater sampling with field measurements. Typically 1–3 days depending on the number of points.
Laboratory analysisChilled samples go to the accredited partner lab with a chain of custody. Analysis takes about 5–14 working days depending on parameters.
Report and data handoverAn engineer-signed field report with lab results and maps, ready for the EIA consultant or agency submission. About 2–4 weeks in total.

What do you receive from SPN?

Well Completion Log: installation details, soil layers, screen length and top-of-casing level
Groundwater level tables and graphs, including data logger records if installed
Piezometric map with groundwater flow direction and gradient
Aquifer test results: K and T from slug or pumping tests, and resistivity sections
Sampling records with field pH, EC, DO and ORP, and chain of custody
Laboratory results from an accredited partner laboratory
Map of sampling points and results, showing exceedances and approximate extent
Field report signed by a licensed civil engineer (Council of Engineers Thailand licence), with site photos, ready to pass to the EIA consultant

Why work with SPN in Thailand?

Coverage: Nationwide, all 77 provinces of Thailand. Office in Bang Sao Thong, Samut Prakan, near Bangkok and Suvarnabhumi Airport.
Scope: Testing, investigation and engineering design only. SPN does not take construction work, so recommendations stay independent.
Reports: Signed by a licensed civil engineer (Council of Engineers Thailand licence) and usable for Thai building permit submissions.
Language: Quotations and coordination in English or Thai.
Quotation: Free quotation within 24 hours. Send drawings, site location or TOR to info@spnth.com or LINE @spnth.

Frequently asked questions about environmental site assessment in Thailand

Does SPN prepare EIA reports?

No. An EIA report must be prepared by a consultant licensed by ONEP (สผ.), so SPN does not prepare it directly. SPN coordinates with licensed EIA partner consultants, so you have one contact for both field work and reporting.

Does SPN have its own contamination laboratory?

No. SPN does not have its own chemical laboratory. Heavy metals, VOCs, TPH and other parameters are analysed by accredited partner laboratories, and SPN coordinates and delivers the samples.

What is a monitoring well and why install one?

A monitoring well is a borehole fitted with PVC casing and screen to measure groundwater level and collect water samples for analysis. It is used to track groundwater quality under EIA conditions around factories, or after a chemical spill.

Can monitoring well installation and water analysis be in one package?

Yes. SPN offers a complete package: monitoring well installation, groundwater sampling, analysis by a partner laboratory and a results report. You receive one quotation and one report; work is priced per project, with a free quotation within 24 hours.

How long does it take from installation to the report?

Field work (installation and sampling) takes 1–3 days depending on the number of points. Laboratory analysis takes 5–14 working days depending on parameters. The total from start to report is about 2–4 weeks.

How many monitoring wells are needed?

To determine groundwater flow direction you need at least 3 wells that are not in a straight line. Typically there is 1 upgradient well and at least 2 downgradient wells for each potential contamination source. The actual number depends on site size, number of sources and the measures in the EIA report.

What is the difference between a slug test and a pumping test?

A slug test changes the water level in a well instantly and measures recovery; it is quick and low-cost in an existing monitoring well but represents only the soil around that well. A pumping test pumps continuously and reads surrounding observation wells, giving values representative of a wider area. It suits dewatering design or water yield assessment but needs more time and equipment.

Can a resistivity survey show whether groundwater is contaminated?

No, it only shows zones of unusual resistivity, which may be caused by saline water, clay layers or some contaminants. It is a screening tool for choosing borehole locations. Contamination must always be confirmed by sampling and laboratory analysis.

How should a disused monitoring well be closed?

It should be closed following ASTM D5299: remove or cut the casing, grout the full depth with bentonite or cement grout, and finish the wellhead flush with the ground. This prevents surface water or contaminants from entering the aquifer through the old well. SPN provides a decommissioning record as evidence.

Other SPN services in Thailand

อ่านหน้านี้เป็นภาษาไทย →