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Title: CWatM + MODFLOW 6 Hydrologist for Surface Water–Groundwater Modeling Job Description: I am looking for a hydrologist / groundwater modeler with experience in CWatM, MODFLOW 6, FloPy/Python, or coupled surface water–groundwater modeling. The study area is the North China Plain, with a simulation period of 2000–2024. Main work includes: - Surface-water modeling using CWatM - Groundwater modeling using MODFLOW - Surface water–groundwater coupling and grid alignment - Representation of the main aquifer groups of the North China Plain - Water withdrawal and water-use representation - Representation of major water-transfer systems, reservoirs, diversion points, pumping stations, and receiving areas/users - A Python-based water allocation / scheduling component for the main transfer network - Streamflow calibration and validation - Groundwater-level validation - GRACE storage comparison - Evapotranspiration validation - Appropriate parameter calibration and sensitivity analysis - Collection and organization of missing publicly available hydrogeological and model-input data when necessary Some streamflow, water-use, groundwater, and reference data are already available. For the water-transfer network, the main source–route–engineering node–receiving area/user relationships are important. Exact route coordinates do not need to be survey-level accurate at the initial stage. The groundwater model should represent the main aquifer groups based on available hydrogeological, borehole, and professional data. The modeling approach and required components are already defined. Please base your quotation on model implementation, adaptation, calibration, and validation, rather than assuming that a completely new hydrological modeling platform needs to be developed from scratch. The exact calibration / sensitivity-analysis method can be proposed based on your experience and the model conditions. Please apply only if you have relevant hands-on experience. When applying, please provide: 1. One or two previous projects most similar to this task. 2. Your experience with MODFLOW 6 and FloPy/Python. 3. Whether you have used CWatM or another coupled surface water–groundwater model. 4. Which parts of this task you can complete yourself. Detailed requirements will be provided to suitable candidates for review and quotation. Keywords / Skills: CWatM MODFLOW 6 FloPy Python Hydrology Hydrogeology Groundwater Modeling Surface Water–Groundwater Modeling Coupled Hydrological Modeling Water Resources Modeling Water Resources Engineering Model Calibration GRACE Evapotranspiration GIS
Project ID: 40704691
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You need a Python-based implementation and calibration workflow combining CWatM, MODFLOW 6, water-transfer allocation, and multi-source validation for the North China Plain from 2000–2024. My strongest relevant experience is Python-based scientific/data processing and complex modeling workflows, including serverless Python and real-time data pipelines at Marin Software. I can handle the Python/FloPy workflow, data preparation, model automation, calibration pipelines, sensitivity analysis, GIS-based processing, and validation against streamflow, groundwater, GRACE, and ET datasets. I want to be transparent that CWatM and MODFLOW 6 are not listed among my direct production projects, so I would first review your existing model structure, inputs, and coupling requirements rather than overstate hands-on experience. Which existing CWatM/MODFLOW components and calibration datasets are already prepared?
$110 USD in 4 days
2.2
2.2
45 freelancers are bidding on average $138 USD for this job

⭐⭐⭐⭐⭐ Experienced Hydrologist for Surface Water-Groundwater Modeling Projects ❇️ Hi My Friend, I hope you are doing well. I've reviewed your project requirements and noticed you're looking for a hydrologist and groundwater modeler. You have no need to look any further; Zohaib is here to help you! My team has successfully completed 50+ similar projects for surface water and groundwater modeling. I will utilize CWatM and MODFLOW 6 to deliver accurate modeling results, ensuring a smooth project flow within your budget. ➡️ Why Me? I can easily handle your hydrological modeling project as I have 5 years of experience in groundwater modeling, surface water modeling, and data validation. My expertise includes CWatM, MODFLOW 6, and Python programming for efficient modeling solutions. Besides, I have a strong grip on related technologies like GIS, GRACE, and model calibration, ensuring a comprehensive approach to your project. ➡️ Let's have a quick chat to discuss your project in detail. I'll showcase samples of my previous work, demonstrating my capabilities in hydrological modeling. Looking forward to discussing this with you in our chat. ➡️ Skills & Experience: ✅ CWatM ✅ MODFLOW 6 ✅ FloPy ✅ Python ✅ Hydrology ✅ Hydrogeology ✅ Groundwater Modeling ✅ Surface Water Modeling ✅ Water Resources Engineering ✅ Model Calibration ✅ GRACE ✅ GIS ✅ Evapotranspiration Waiting for your response! Best Regards, Zohaib
$150 USD in 2 days
7.9
7.9

Hi, I can implement the CWatM–MODFLOW 6 workflow, align grids, build the aquifer and withdrawal representations, and set up the Python allocation logic in FloPy. I would then handle calibration and validation against streamflow, groundwater levels, GRACE, and ET, using publicly available hydrogeologic inputs where needed. Best regards, Sujeewa GISPromo IT Solutions
$140 USD in 5 days
7.3
7.3

Hi, I am a hydrological modeler with 8 years of rich experience in environmental and water resources modeling, with a background in groundwater modeling, Python based data processing, GIS, geospatial analysis, and model calibration. I am familiar with Python, MODFLOW 6, FloPy, CWatM, groundwater modeling, surface water modeling, GIS, remote sensing, statistical analysis, simulation, and water resources engineering. For the North China Plain study, I can work on the CWatM and MODFLOW 6 implementation, grid alignment and surface water groundwater interaction, aquifer representation, water withdrawals and transfer systems, and Python based water allocation components. I can also support calibration and validation using streamflow, groundwater levels, GRACE storage, and evapotranspiration data, together with sensitivity analysis and organization of missing model inputs. I'm an individual freelancer and can work on any time zone you want. Please contact me with the best time for you to have a quick chat. Looking forward to discussing more details. Thanks. Emile.
$250 USD in 7 days
5.8
5.8

As a highly skilled hydrologist and groundwater modeler, I bring extensive expertise in using CWatM, MODFLOW 6, and FloPy/Python for coupled surface water–groundwater modeling, making me the ideal fit for your North China Plain project. I have successfully completed several projects similar to this task, particularly in surface water and groundwater modeling - tasks that are core to your project. Moreover, I'm experienced with calibration and validation which will prove vital as we compare hydrologic data like streamflow, groundwater levels, GRACE storage, and evapotranspiration. Over the years, I have worked on a wide range of projects which has equipped me with excellent problem-solving skills and adaptability – essential traits when dealing with missing public hydrogeological or model-input data. My experiences employing the latest tools such as GIS will aid in the efficient collection and organization of any missing data we might encounter in our simulation process. Working with AI computational programs including CWatM, MODFLOW 6, and FloPy/Python has honed my programming skills which will ensure a smooth implementation process throughout the simulation period of 2000–2024.
$96 USD in 2 days
6.0
6.0

Coupling CWatM and MODFLOW 6 demands careful grid alignment. I build coupled models using FloPy and Python, generating the CWatM surface water model and MODFLOW 6 groundwater model for the North China Plain, representing aquifer groups and water infrastructure you detailed. This also includes a Python component for water allocation, creating the surface water, groundwater system you need. What are the specific resolution requirements for the CWatM and MODFLOW 6 grids? I need the study area shapefile to begin. 5.0 rating across 10 reviews on here, and Preferred Freelancer status.
$140 USD in 21 days
5.2
5.2

Your coupled model will fail calibration if the CWatM–MODFLOW exchange flux isn't mass-conservative at daily timesteps. I've debugged this exact issue on a regional aquifer system where flux imbalance caused 15% error in storage trends compared to GRACE. Quick questions - what's your current strategy for handling the multi-layer confined/unconfined aquifer transitions in the North China Plain? And are you planning PEST++ or manual calibration given the 24-year runtime? Here is the architectural approach: - MODFLOW 6 + FLOPY: Build 3-layer model representing shallow unconfined, middle confined, and deep confined aquifers using borehole logs, then couple to CWatM via API exchange with daily stress periods for mass balance closure. - PYTHON WATER ALLOCATION: Develop priority-based routing algorithm for South-to-North transfer using NetworkX to handle reservoir releases, pumping constraints, and demand nodes with monthly allocation rules. - CALIBRATION FRAMEWORK: Implement PEST++ with pilot points for hydraulic conductivity and specific yield, targeting streamflow NSE >0.6, groundwater RMSE <5m, and GRACE trend match within 10% using 2000-2015 calibration and 2016-2024 validation. I've built similar coupled models for two transboundary aquifer systems in Central Asia and validated against GRACE mascons. Let's schedule a 20-minute call to review your existing data structure and finalize the calibration strategy before quoting.
$130 USD in 3 days
5.4
5.4

Hi ClientFirstName, Your model already has the hard part defined , the hidden risk is not building a new platform, but making CWatM and MODFLOW 6 talk cleanly at the right spatial and temporal scale. I’ve worked on Python-based water modeling, GIS-driven data organization, and model implementation workflows, and I can help adapt the surface-water / groundwater coupling, grid alignment, calibration setup, and validation against streamflow, groundwater levels, GRACE, and evapotranspiration. I’m comfortable working in FloPy/Python for model control, water allocation logic, and organizing missing hydrogeological inputs into a consistent modeling framework. I’ve shared an initial estimate based on your description, and once we go over a few technical or functional details, I’ll confirm the exact cost and delivery schedule. Could you share which CWatM/MODFLOW 6 components are already implemented and which still need adaptation or calibration? Can you share which CWatM/MODFLOW components are already built and which still need implementation or calibration? Are the aquifer groups and transfer-network relationships already mapped in GIS form? Which validation datasets are most complete for the 2000-2024 period? Looking forward to your reply so we can finalize the exact plan. Best regards, Asad
$95 USD in 5 days
5.2
5.2

Hi there, CWatM + MODFLOW 6 coupling, grid alignment, and calibration for the North China Plain need careful implementation to keep streamflow, groundwater levels, and GRACE comparisons consistent. I have strong hands-on experience with Python and hydrology workflows and have solved similar problems involving simulation setup, groundwater model validation, and data-driven calibration. My approach would be to: * Review the existing code, architecture, logs, or current implementation. * Identify the root cause and determine what can be reused versus what needs to be changed. * Implement a clean, maintainable solution using Python, FloPy, and coupled surface water-groundwater modeling methods. * Test edge cases, reliability, performance, security, and integration behavior. * Deploy or integrate the fix without disrupting the existing system. A key point here is keeping the MODFLOW 6 package structure, stress periods, and allocation logic synchronized with CWatM so mass balance and timing remain stable. I prefer fixing the actual root cause rather than applying temporary patches, and I will keep the implementation simple, stable, and maintainable. I can start by reviewing the current model setup and proceed with the most practical solution. Best regards, Ian
$155 USD in 5 days
4.8
4.8

Hello, I can implement and calibrate the defined CWatM + MODFLOW 6 workflow for the North China Plain using Python/FloPy and GIS-based preprocessing. I’ll focus on adapting the existing modeling approach rather than rebuilding a platform from scratch. I’ll configure the MODFLOW 6 aquifer framework, boundary conditions, pumping/water use and surface-water interactions, align the CWatM and groundwater grids, and represent the major transfer systems, reservoirs, diversion points and receiving areas at an appropriate modeling scale. I’ll build the Python water-allocation/scheduling component, organize missing public inputs, and establish reproducible preprocessing and model runs. Calibration and validation will cover streamflow, groundwater levels, GRACE storage and evapotranspiration, with sensitivity analysis and documented parameter selection. I can handle the modeling, Python/FloPy workflows, GIS processing, calibration and validation end-to-end. Looking forward to work with you. Thanks
$120 USD in 2 days
4.7
4.7

Hi there, As a hydrologist and groundwater modeler with extensive experience using CWatM, MODFLOW 6, and FloPy/Python, I'm confident in my ability to handle the complexities of your project. My expertise aligns perfectly with your requirements for surface water–groundwater modeling, representing aquifer groups, validating streamflow and groundwater levels, conducting GRACE storage comparisons, and more. Additionally, my skills in Python allow me to develop a water allocation / scheduling component for the transfer network seamlessly. In terms of relevant experience, I've worked on projects that share similarities with your task. For example..... With these experiences, I've honed my skills not only in model implementation but also in adapting, calibrating, and validating these models – which is crucial for a project of this nature. Best regards, Mobasher Reza
$140 USD in 3 days
4.8
4.8

As a multitalented hydrologist, groundwater modeler, and full-stack developer with extensive experience in Python, I'm confident that I can deliver exceptional results for your Surface Water–Groundwater Modeling project. In terms of hydrological modeling, I've had the privilege of working on similar projects that entailed the use of CWatM, MODFLOW 6, and FloPy/Python - precisely what you're seeking. This experience grants me an understanding of the complexities and nuances involved in surface water and groundwater coupling. One of my primary strengths lies in my adaptability and precision when refining pre-existing models. You mentioned that your modeling approach and many required components are already defined; this aligns perfectly with my skill sets. My expertise will be pivotal in implementing, adapting, calibrating, and validating the models to meet your study area's needs - North China Plain. Furthermore, I highly value data completeness, a crucial facet for hydrological modeling. While you've mentioned that some data is already available, I'm comfortable organizing collected data as well as identifying and procuring any missing public hydrogeological or model-input data to ensure the utmost accuracy in our work. To summarize, I possess the proficiency you're looking for in a modeller with respect to code implementation, adaptation & improvement all while aligned closely with your demands.
$100 USD in 2 days
4.4
4.4

Hello, Primary risk is mismatched grids and inconsistent exchange fluxes when coupling CWatM and MODFLOW 6 across the North China Plain leading to biased groundwater trends and incorrect agricultural withdrawals. I lock grid alignment and exchange terms early to prevent mass balance drift and ensure comparability with GRACE storage signals. I have delivered surface-water and groundwater integrations for agricultural basins and water-transfer corridors, performing scripted model assembly, calibration, and validation. I will reuse a FloPy/Python workflow for model build, parameter assignment, and automated calibration so changes to CWatM routing or withdrawal schedules are propagated into MODFLOW 6 without manual regridding. I implement an initial mass-balance check and run 3-year spin-up before the 2000 start to stabilize initial heads and storages. I begin by ingesting available hydrogeological layers and CWatM outputs, produce a matched MODFLOW 6 discretization, and implement a Python-based allocation/scheduling routine that writes time-series boundary and well packages. Calibration targets will include streamflow, groundwater-levels, evapotranspiration, and GRACE storage anomalies. - Which of the model inputs can you provide now (boundary conditions, well locations, CWatM outputs, observed heads/streamflow)? - Would you prefer parameter estimation with PEST++ or a FloPy/Python-driven local-global calibration loop? Regards, Thomas Beigbeder
$230 USD in 3 days
4.2
4.2

Hi, there. "SURFACE WATER–GROUNDWATER MODELING" — you need a calibrated model workflow for reliable water resource analysis. I would focus on adapting the defined CWatM and MODFLOW 6 approach rather than rebuilding a new platform. I would organize the model inputs, align surface and groundwater grids, connect water-use components, and validate results against available observations. I can work with Python/FloPy workflows for MODFLOW 6 setup, data processing, GIS preparation, calibration, sensitivity analysis, and validation tasks. I would compare simulated streamflow, groundwater levels, GRACE storage, and evapotranspiration to improve model reliability. For the North China Plain case, I would structure the water-transfer network and aquifer representation from available hydrogeological and operational data so the model remains practical for future updates. Which components are already available: an existing CWatM/MODFLOW model setup, or only the observation and input datasets? Looking forward to working with you.
$30 USD in 1 day
3.7
3.7

Hi, I’m very interested in this project because it combines scientific modeling, numerical methods, Python engineering, and large-scale data processing—areas that strongly align with my engineering background. I would structure the solution as a reproducible pipeline: CWatM surface hydrology → spatial/temporal grid alignment → MODFLOW 6 groundwater system → Python/FloPy coupling → transfer-network allocation → multi-source calibration and validation. My focus would be on robust data preprocessing, aquifer/grid parameterization, recharge and withdrawal exchange, and a modular Python allocation engine for source–route–node–user scheduling. For calibration, I’d use parameter sensitivity and objective functions combining streamflow, groundwater heads, ET, and GRACE storage while maintaining time-based validation. I bring strong Python, mathematical modeling, optimization, and data-analysis skills and can build the workflow to remain reproducible and maintainable. Best regards, Gustavo
$140 USD in 7 days
3.7
3.7

Hello, With my background in Python (data processing, FloPy), AWS EC2 (cloud computation), full-stack development (Java Spring Boot, MySQL for data management), Tableau (visualization), and journalism experience for clear documentation, I can deliver a robust, validated hydrological modeling framework. I can implement and calibrate a coupled surface water–groundwater model for the North China Plain using CWatM and MODFLOW 6, with Python/FloPy integration. Deliverables: • Surface water modeling with CWatM • Groundwater modeling with MODFLOW 6 representing main aquifer groups • Coupling and grid alignment between surface and groundwater models • Representation of water withdrawals, transfer systems, reservoirs, diversion points, and pumping stations • Python-based water allocation/scheduling component for the transfer network • Calibration and validation: streamflow, groundwater levels, GRACE storage, evapotranspiration • Parameter calibration and sensitivity analysis • Organized input data and reproducible scripts Timeline: 6 weeks Looking forward to working on your project. Best regards, Somee
$250 USD in 42 days
3.2
3.2

Hi , You need an expert in Civil Engineering, Data Processing, Geology, Statistical Analysis, Geographical Information System (GIS), Remote Sensing, Python, Simulation, Geospatial and Environmental Engineering, and I have a tailor-made solution ready for you. Your project brief instantly reminded me of a recent client who faced similar challenges, and I know exactly how to execute this flawlessly for your specific needs. To ensure we hit the ground running, I have three quick questions: Are there any additional technical details or constraints not mentioned in the brief? What is the primary hurdle currently blocking your progress on this? What is your strict timeline for completion? Why trust me with your project? The Record: 250+ Projects. 6+ Years. 100+ consecutive 5-star reviews. The Standard: Zero misses. I don’t just finish the job; I guarantee flawless execution. The Availability: Full-time freelancer, online 9 AM - 9 PM EST. My biggest "heavy-hitter" projects are kept off my public portfolio to protect client confidentiality. Click 'CHAT', and I’ll immediately send over relevant, private samples so you can see the standard of my work firsthand. Best regards, Muhammad Arsalan
$30 USD in 2 days
2.5
2.5

Hello, Having completed numerous projects involving hydrology, hydrogeology, and groundwater modeling, I am well-equipped to undertake your North China Plain study using CWatM and MODFLOW 6. Moreover, I have extensive experience with FloPy/Python, making me competent in assimilating Python-based water allocation/scheduling components for transfer networks. My adeptness with these tools will ensure optimal implementation and calibration of the model as per your specifications. As a seasoned professional, I understand the significance of precise representation of each component within the system, ensuring streamflow, water withdrawal/utilization, and groundwater level validation align with actual data. Garnering publicly available hydrogeological and model-input data is another strength area that I possess. With a meticulous approach towards implementation, adaptation, calibration, and validation, you can trust me to ensure robust simulation results. In addition to my technical skills in CWatM + MODFLOW 6 - FloPy/Python-based modeling I bring ethical values like client-centricity and punctuality. Furthermore, with full commitment to the project's success, I guarantee open channels of communication for you to provide continuous feedback. This ensures that any potential changes or newly met requirements are addressed promptly; a vital aspect given the need for an exact route coordinates mapping at later stages. Trust me as your Hydrolo Thanks!
$155 USD in 4 days
3.4
3.4

I'm a certified Data Analyst and Python & R developer specializing in EDA, statistical analysis, data automation, and web scraping. My hands-on toolkit includes Python (Pandas, NumPy), R, Selenium, Playwright, Power BI, Flask, more over I can all the related to python and R languages. I don't just deliver code — I deliver working solutions that save your time and reduce manual effort. I also work with health and genomics data, applying statistical methods from my ongoing Data Science for Health specialization — useful if your project involves research-grade or health-related datasets. I hold certifications in AI Development (IBM) and Python Automation & Data Science (Coursera & Packt), so you can trust that my work is professional and up to standard. I'm available to start immediately, communicate regularly, and will not close the contract until you are 100% satisfied. Let's discuss your project — feel free to send me a message!
$70 USD in 7 days
2.0
2.0

Hi there, The challenge lies in accurately coupling surface water and groundwater models while ensuring proper calibration and validation across the North China Plain. A clear understanding of the aquifer groups and their interactions with water transfer systems is crucial. I have hands-on experience with MODFLOW 6 and FloPy, enabling effective groundwater modeling and calibration. Additionally, I can implement a Python-based component for water allocation within the transfer network, ensuring accurate representation of water use and withdrawal. Which specific aspects of the calibration and validation process are you looking for support with? Thank you.
$140 USD in 7 days
0.0
0.0

You need a fully coupled CWatM plus MODFLOW 6 model of the North China Plain spanning 2000 to 2024, with water allocation logic for major inter-basin transfers, multi-variable calibration, and GRACE validation baked in from the start, not bolted on afterward. My approach is straightforward. I would begin with data audit and grid harmonization, aligning CWatM spatial resolution with MODFLOW 6 unstructured or structured grids covering the shallow and deep aquifer groups of the NCP. FloPy handles all MODFLOW setup and I would extend CWatM's routing module to pass recharge, return flows, and stream-aquifer exchange fluxes back and forth at each stress period. The water transfer network, including South-North Transfer routes, reservoirs, and pumping stations, gets a dedicated Python scheduling component with priority rules and mass-balance checks. Calibration runs PEST-HP or similar against streamflow, groundwater levels, ET, and GRACE TWSA simultaneously, followed by sensitivity analysis via Morris or Sobol screening. I have hands-on experience with FloPy, CWatM configuration, and coupled modeling in data-scarce transboundary basins, including aquifer parameterization from sparse borehole records, which is exactly the NCP challenge. Realistic timeline is roughly 16 to 20 weeks depending on data completeness. One key risk I always address early is vertical discretization of the confined and unconfined aquifer boundary, since getting that wrong propagates through every calibration metric. What spatial resolution and stress-period length are you currently targeting for the coupled runs?
$138.70 USD in 7 days
0.0
0.0

Jiaozuo, China
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